Yogo sapphires are blue sapphires, a colored variety of
corundum
Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the pres ...
, found in
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
, primarily in Yogo Gulch (part of the
Little Belt Mountains
The Little Belt Mountains are a section of the Rocky Mountains in the U.S.
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It cons ...
) in
Judith Basin County, Montana
Judith Basin County is a county in the U.S. state of Montana. As of the 2020 census, the population was 2,023. Its county seat is the town of Stanford.
History
Judith Basin County was formed of area taken from western Fergus and eastern Casca ...
. Yogo sapphires are typically
cornflower blue, a result of trace amounts of
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
and
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
. They have high uniform clarity and maintain their brilliance under artificial light. Because Yogo sapphires occur within a vertically
dipping resistive
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels ...
igneous
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...
dike
Dyke (UK) or dike (US) may refer to:
General uses
* Dyke (slang), a slang word meaning "lesbian"
* Dike (geology), a subvertical sheet-like intrusion of magma or sediment
* Dike (mythology), ''Dikē'', the Greek goddess of moral justice
* Dikes, ...
, mining efforts have been sporadic and rarely profitable. It is estimated that at least 28 million carats () of Yogo sapphires are still in the ground. Jewelry containing Yogo sapphires was given to First Ladies
Florence Harding
Florence Mabel Harding (née Kling; August 15, 1860 – November 21, 1924) was the first lady of the United States from 1921 until her husband's death in 1923 as the wife of President Warren G. Harding.
Florence first married Pete De Wolfe ...
and
Bess Truman
Elizabeth Virginia Truman ('' née'' Wallace; February 13, 1885October 18, 1982) was the wife of President Harry S. Truman and the first lady of the United States from 1945 to 1953. She also served as the second lady of the United States from Ja ...
; in addition, many gems were sold in Europe, though promoters' claims that Yogo sapphires are in the
crown jewels of England or the engagement ring of
Princess Diana
Diana, Princess of Wales (born Diana Frances Spencer; 1 July 1961 – 31 August 1997) was a member of the British royal family. She was the first wife of King Charles III (then Prince of Wales) and mother of Princes William and Harry. Her ac ...
are dubious. Today, several Yogo sapphires are part of the
Smithsonian Institution's gem collection.
Yogo sapphires were not initially recognized or valued. Gold was discovered at Yogo Creek in 1866, and though "blue pebbles" were noticed alongside gold in the stream
alluvium
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...
by 1878, it was not until 1894 that the "blue pebbles" were recognized as sapphires. Sapphire mining began in 1895 after a local rancher named Jake Hoover sent a cigar box of gems he had collected to an assay office, which in turn sent them to
Tiffany's
Tiffany & Co. (colloquially known as Tiffany's) is a high-end luxury jewelry and specialty retailer, headquartered on Fifth Avenue in Manhattan. It sells jewelry, sterling silver, porcelain, crystal, stationery, fragrances, water bottles, watc ...
in New York, where an appraiser pronounced them "the finest precious gemstones ever found in the United States". Hoover then purchased the original
mother lode from a sheepherder, later selling it to other investors. This became the highly profitable "English Mine", which flourished from 1899 until the 1920s. A second operation, the "American Mine", was owned by a series of investors in the western section of the Yogo dike, but was less profitable and bought out by the syndicate that owned the English Mine. In 1984, a third set of claims, known as the Vortex mine, opened.
The term "Yogo sapphire" is the preferred wording for gems found in the Yogo Gulch, whereas "Montana sapphire" generally refers to gems found in other Montana locations. More gem-quality sapphires are produced in Montana than anywhere else in North America. Sapphires were first discovered in Montana in 1865, in alluvium along the
Missouri River. Finds in other locations in the western half of the state occurred in 1889, 1892, and 1894. The Rock Creek location, near
Phillipsburg, is the most productive site in Montana, and its gems inspired the name of the nearby
Sapphire Mountains
The Sapphire Mountains are a range of mountains located in southwestern Montana in the northwestern United States. From a point near the Clark Fork River and the city of Missoula, they run in a southerly direction for a distance of approximately ...
. In 1969, the sapphire was co-designated along with the
agate
Agate () is a common rock formation, consisting of chalcedony and quartz as its primary components, with a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks. The ornamental use of agate was common in Ancie ...
as Montana's
state gemstone
Leaders of states in the U.S. which have significant mineral deposits often create a state mineral, rock, stone or gemstone to promote interest in their natural resources, history, tourism, etc. Not every state has an official state mineral, rock, ...
s.
In the early 1980s, Intergem Limited, which controlled most of the Yogo sapphire mining at the time, rocked the gem world by marketing Yogo sapphires as the world's only guaranteed "untreated" sapphire, exposing a practice of the time wherein 95 percent of all the world's sapphires were heat-treated to enhance their natural color. Although Intergem went out of business, the gems it mined appeared on the market through the 1990s because the company had paid its salesmen in sapphires during its financial demise.
Citibank
Citibank, N. A. (N. A. stands for " National Association") is the primary U.S. banking subsidiary of financial services multinational Citigroup. Citibank was founded in 1812 as the City Bank of New York, and later became First National City ...
had obtained a large stock of Yogo sapphires as a result of Intergem's collapse, and after keeping them in a vault for nearly a decade, sold its collection in 1994 to a Montana jeweler. Mining activity today is largely confined to hobby miners in the area; the major mines are currently inactive.
Location
Yogo sapphires are mined in Montana at Yogo Gulch (
), which is in
Judith Basin County, Montana
Judith Basin County is a county in the U.S. state of Montana. As of the 2020 census, the population was 2,023. Its county seat is the town of Stanford.
History
Judith Basin County was formed of area taken from western Fergus and eastern Casca ...
, southwest of
Utica, west-southwest of
Lewistown, and east of
Great Falls
Great may refer to: Descriptions or measurements
* Great, a relative measurement in physical space, see Size
* Greatness, being divine, majestic, superior, majestic, or transcendent
People
* List of people known as "the Great"
*Artel Great (born ...
. The site was in
Fergus County when Yogo sapphires were discovered, but in 1920, because of the re-designation of county boundaries, Judith Basin County was carved out from parts of western Fergus County and eastern
Cascade County.
Yogo Gulch and the corresponding natural features of Yogo Peak (), Yogo Creek, and the Yogo dike, where the gems are mined, are all in the
Little Belt Mountains
The Little Belt Mountains are a section of the Rocky Mountains in the U.S.
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It cons ...
within Judith Basin County. The Gulch is located along the lower reaches of Yogo Creek and west of the
Judith River
The Judith River is a tributary of the Missouri River, approximately 124 mi (200 km) long, running through central Montana in the United States. It rises in the Little Belt Mountains and flows northeast past Utica and Hobson. It is ...
. The west end of the Yogo dike outcrops just southwest of Yogo Creek, about north of Yogo Creek's confluence with the Middle Fork of the Judith River; from there it runs east-northeast and ends about from the Judith River. Yogo Creek starts just south of Yogo Peak, which is about west of the Judith River. From there the creek flows southeast into the Middle Fork of the Judith River. The Judith River then flows northeast from the Little Belts toward Utica. East of the Judith River is Pig-Eye Basin, where Jake Hoover, credited as the person who discovered Yogo sapphires, owned a
ranch
A ranch (from es, rancho/Mexican Spanish) is an area of land, including various structures, given primarily to ranching, the practice of raising grazing livestock such as cattle and sheep. It is a subtype of a farm. These terms are most often ...
.
Etymology
Because Yogo Gulch lies in a region historically inhabited by the
Piegan Blackfeet
The Piegan ( Blackfoot: ''Piikáni'') are an Algonquian-speaking people from the North American Great Plains. They were the largest of three Blackfoot-speaking groups that made up the Blackfoot Confederacy; the Siksika and Kainai were the oth ...
people, promoters of Yogo sapphires claim that ''yogo'' may mean "romance" or "blue sky" in the
Blackfoot language
The Blackfoot language, also called Siksiká (its denomination in ISO 639-3, ; Siksiká ik͡siká syllabics ), often anglicised as ', is an Algonquian language spoken by the Blackfoot or ''Niitsitapi'' people, who currently live in the nort ...
, although there is little evidence to support this claim. Other meanings for ''yogo'' have been suggested, including "
Going over the hill". The meaning of the word "Yogo" had been lost by 1878, when
placer gold was found in Yogo Creek. Thus, its true meaning is uncertain.
Mineralogy and geology
![Cornflower blue Yogo sapphire](https://upload.wikimedia.org/wikipedia/commons/1/1d/Cornflower_blue_Yogo_sapphire.jpg)
Sapphires are a color variety of
corundum
Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the pres ...
, a crystalline form of
aluminium oxide (). Corundum is one of the hardest minerals, rating 9 on the
Mohs scale
The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material.
The scale was introduced in 1812 by th ...
. Corundum gems of most colors are called sapphires, except for red ones, which are called
rubies
A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sap ...
. The term "Yogo sapphire" refers only to sapphires from the Yogo Gulch. The cornflower blue color of the Yogo results from trace amounts of
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
and
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
. Yogo sapphires are unique in that they are free of cavities and
inclusions, have high uniform clarity, lack
color zoning, and do not need heat treating because their cornflower blue coloring is uniform and deep. Unlike Asian sapphires, they maintain their brilliance in artificial light. Yogo sapphires present an advantage to gemcutters: since they are found as primary constituent minerals within an
igneous
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...
bedrock
In geology, bedrock is solid Rock (geology), rock that lies under loose material (regolith) within the crust (geology), crust of Earth or another terrestrial planet.
Definition
Bedrock is the solid rock that underlies looser surface mater ...
rather than in sedimentary
alluvial
Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...
deposits where most other sapphires are located, they retain a perfect or near perfect crystalline shape, making cutting much easier, as does their lack of inclusions, color zoning, or cloudiness. Yogo sapphires also exhibit a triangular pattern on the basal plane of the flattened crystals, with thin
rhombohedral
In geometry, a rhombohedron (also called a rhombic hexahedron or, inaccurately, a rhomboid) is a three-dimensional figure with six faces which are rhombus, rhombi. It is a special case of a parallelepiped where all edges are the same length. It c ...
crystal faces, a feature absent in sapphires from other parts of Montana.
Yogo sapphires tend to be beautiful, small, and very expensive. The
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
and many gem experts have stated that Yogo sapphires are "among the world's finest sapphires." The roughs tend to be small and flat, so cut Yogo gems heavier than are rare. Only about 10 percent of cut pieces are over . The largest recorded Yogo rough, found in 1910, weighed and was cut into an gem. The largest cut Yogo is . Because of the rarity of large rough Yogo sapphires, Yogo gem prices begin rising sharply when they are over , and skyrocket when they are over .
Montana sapphires in general come in a variety of colors, but Yogo sapphires are almost always blue. About two percent of Yogo sapphires are purple, due to trace amounts of
chromium
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and hardne ...
. A very small number of rubies have been found at Yogo Gulch.
Yogo sapphires were first discovered in alluvial streambed sediments during
gold mining
Gold mining is the extraction of gold resources by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. However, with the expansion of gold mining to ores that are not on the surface ...
operations in Yogo Gulch downstream from the Yogo dike, but were later traced to their source within igneous bedrock. Worldwide, other than the Yogo Gulch deposit and one small site in the
Kashmir
Kashmir () is the northernmost geographical region of the Indian subcontinent. Until the mid-19th century, the term "Kashmir" denoted only the Kashmir Valley between the Great Himalayas and the Pir Panjal Range. Today, the term encompas ...
region, most other corundum is mined from the sand and gravel created by the weathering of
metamorphic rock
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...
. Alluvial sapphires are found in the
Far East
The ''Far East'' was a European term to refer to the geographical regions that includes East and Southeast Asia as well as the Russian Far East to a lesser extent. South Asia is sometimes also included for economic and cultural reasons.
The ter ...
, Australia, and in three other Montana locations—the upper
Missouri River,
Rock Creek Rock Creek or Rockcreek may refer to:
Streams
United States
* Rock Creek (California)
* Rock Creek (Fountain Creek tributary), Colorado
* Rock Creek (Idaho)
* Rock Creek (Kankakee River tributary), Illinois
* Rock Creek (Wapsipinicon River tribut ...
, and
Dry Cottonwood Creek. The location of most Yogo sapphires within igneous rock rather than from alluvial placer deposits requires difficult hard rock mining. Coupled with American labor costs, this makes their extraction fairly expensive. At least are estimated to still be in the ground. The Yogo dike is "the only known igneous rock from which sapphire is mined".
The sapphire bearing Yogo dike is a dark gray to green
intrusive rock
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''Igneous intrusion, intrusions'', such as batholiths, dike (geology), dikes, Sill (geology), sills, laccoliths, and volcanic necks.I ...
known as a
lamprophyre
Lamprophyres () are uncommon, small-volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks, and small intrusions. They are alkaline silica-undersaturated mafic or ultramafic rocks with high magnesium oxid ...
. The lamprophyre is an unusual igneous rock that contains a low content of
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
. The rock has a
porphyritic
Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning all ...
texture with large crystals of
orthopyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
and
phlogopite
Phlogopite is a yellow, greenish, or reddish-brown member of the mica family of phyllosilicates. It is also known as magnesium mica.
Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula KMg3AlSi3O ...
set in a fine grained
matrix
Matrix most commonly refers to:
* ''The Matrix'' (franchise), an American media franchise
** ''The Matrix'', a 1999 science-fiction action film
** "The Matrix", a fictional setting, a virtual reality environment, within ''The Matrix'' (franchis ...
. The phlogopite crystals have been used to determine the age of the dike and its crystallization temperature (900 °C (1,650 °F)). The dike also contains fragments of other rock types. These
xenolith
A xenolith ("foreign rock") is a rock fragment (country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusively used to describe inclusions in igne ...
s include pieces of limestone,
clastic
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...
sedimentary rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
s, and
gneiss
Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...
. In some locations, due to the abundance of xenoliths, the dike has the appearance of a limestone
breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix.
The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of di ...
in an igneous matrix. One gneiss fragment found as a xenolith contains corundum. The Yogo sapphires themselves are rimmed with a reaction layer of
spinel
Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals.
Properties
S ...
and are etched, indicating that the sapphires were not in
chemical equilibrium
In a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the sy ...
with their host, the lamprophyre magma. This suggests the sapphire crystals may have originated in an earlier rock, such as a corundum-bearing gneiss, later assimilated by the lamprophyre magma at depth. Earlier investigators had assumed that the sapphire had crystallized from the magma with the necessary high aluminium content provided by assimilation of clay rich
shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...
s of the
Proterozoic
The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...
Belt Supergroup
The Belt Supergroup is an assemblage of primarily fine-grained sedimentary rocks and mafic intrusive rocks of late Precambrian (Mesoproterozoic) age. It is more than thick, covers an area of some 200,000 km2 (77,220 sq. mi), and is considered ...
sediments which are known to be present at depth in the region.
![PurpleY6Br](https://upload.wikimedia.org/wikipedia/commons/7/77/PurpleY6Br.jpg)
The Yogo dike is a narrow subvertical sheet-like igneous body. It varies from thick and extends for ,
striking
Strike may refer to:
People
*Strike (surname)
Physical confrontation or removal
*Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm
*Airstrike, military strike by air forces on either a suspected ...
at an azimuth of 255°. The dike is broken into three offset
en echelon
An echelon formation () is a (usually military) formation in which its units are arranged diagonally. Each unit is stationed behind and to the right (a "right echelon"), or behind and to the left ("left echelon"), of the unit ahead. The name of ...
segments, and dates to 48.6
mya
Mya may refer to:
Brands and product names
* Mya (program), an intelligent personal assistant created by Motorola
* Mya (TV channel), an Italian Television channel
* Midwest Young Artists, a comprehensive youth music program
Codes
* Burmese ...
using
Ar dating on phlogopite. The dike intrudes
Mississippian age
The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly ...
(360 to 325 mya) limestone and other sedimentary rocks of the
Madison Madison may refer to:
People
* Madison (name), a given name and a surname
* James Madison (1751–1836), fourth president of the United States
Place names
* Madison, Wisconsin, the state capital of Wisconsin and the largest city known by this ...
and
Big Snowy Group
The Big Snowy Group is a stratigraphical unit of Chesterian age in the Williston Basin.
It takes the name from Big Snowy Mountains in Montana, and was first described on the north slopes of the mountain by H.W. Smith in 1935.
Lithology
Subdiv ...
s.
There has been considerable debate over the years as to the depth of the Yogo dike and how many ounces of rough sapphires per ton it contains. In the late 1970s and early 1980s, Delmer L. Brown, a
geological engineer
Geological engineering is a discipline of engineering concerned with the application of geological science and engineering principles to fields, such as civil engineering, mining, environmental engineering, and forestry, among others.M. Diederichs, ...
and gemologist, conducted the most thorough scientific exploration up to that time, concluding that the dike was at least deep and that the concentration of rough sapphires was not constant throughout the deposit. Brown found that the dike had intruded into a pre-existing
fault that had been a conduit for groundwater circulation. The overlying shale, the
Kibbey Formation, was deposited on an
unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...
, an ancient Mississippian-age
karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...
erosion surface
In geology and geomorphology, an erosion surface is a surface of rock or regolith that was formed by erosion and not by construction (e.g. lava flows, sediment deposition) nor fault displacement. Erosional surfaces within the stratigraphic reco ...
, and was not intruded by the dike. This groundwater action produced collapsed zones which were intruded by the dike to form breccia zones. Recent erosion in the area removed the overlying shales and again exposed the limestone to groundwater action which produced collapse breccias which include fragments of the dike rock. He determined that the erosion of the dike in the current erosion cycle was minimal.
Brown also showed that the unique characteristics of the Yogo sapphires are related to their geological history. Most sapphires are formed under low pressure and temperature over geologically short periods of time, and this is why most non-Yogo sapphires have imperfections and inconsistent coloring. Yogo sapphires show crystalline formation under very high temperatures and pressures corresponding to a great depth, over geologically long periods of time. Brown also showed that distribution of gem rough through the dike was not consistent, so using an average "ounces per ton" was misleading. For example, the section which, despite several ownership and name changes over the years, is generally known as the "American Mine," was developed in an area dominated by post-dike breccia with significantly lower ounces per ton than the English Mine.
Montana sapphires
![LgYellowSapphire](https://upload.wikimedia.org/wikipedia/commons/c/c4/LgYellowSapphire.jpg)
"Yogo sapphire" is the preferred term for gems found in the Yogo Gulch, whereas "Montana sapphire" generally refers to gems found in other Montana locations. More gem-quality sapphires are produced in Montana than anywhere else in North America. Montana sapphires come in a variety of colors, though rubies are rare.
The first sapphires found in the United States were discovered on May 5, 1865, along the Missouri River, about east of
Helena
Helena may refer to:
People
*Helena (given name), a given name (including a list of people and characters with the name)
*Katri Helena (born 1945), Finnish singer
*Helena, mother of Constantine I
Places
Greece
* Helena (island)
Guyana
* ...
, in
Lewis and Clark County
Lewis and Clark County is a County (United States), county located in the U.S. state of Montana. As of the 2020 United States census, 2020 census, the population was 70,973. Its county seat is Helena, Montana, Helena, the state capital. The nume ...
, by Ed "Sapphire" Collins. Collins sent the sapphires to
Tiffany's
Tiffany & Co. (colloquially known as Tiffany's) is a high-end luxury jewelry and specialty retailer, headquartered on Fifth Avenue in Manhattan. It sells jewelry, sterling silver, porcelain, crystal, stationery, fragrances, water bottles, watc ...
in New York City, and to Amsterdam for evaluation; however, those sapphires were of poor coloring and low overall quality, garnering little notice and giving Montana sapphires a poor reputation. Corundum was also found at Dry Cottonwood Creek near
Butte
__NOTOC__
In geomorphology, a butte () is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and tablelands. The word ''butte'' comes from a French word mea ...
in 1889, Rock Creek near
Philipsburg in 1892, and Quartz Gulch near
Bozeman
Bozeman is a city and the county seat of Gallatin County, Montana, United States. Located in southwest Montana, the 2020 census put Bozeman's population at 53,293, making it the fourth-largest city in Montana. It is the principal city of th ...
in 1894. By 1890, the English-owned Sapphire and Ruby Mining Company had bought several thousand acres of land where Montana sapphires were found, but the venture failed after a few years because of fraudulent practices by the owners.
Sapphires from these three sites are routinely heat-treated to enhance color. While millions of carats of sapphires have been mined from the Missouri River deposits, there has been little commercial activity there since the 1990s because of the high cost of recovery and environmental concerns. Production at Dry Cottonwood Creek has been sporadic and low-yielding. The Rock Creek area, also known as Gem Mountain, continues to be the most productive site in Montana, even more so than Yogo Gulch, producing over of sapphires since its inception in 1906. Other than Yogo, Montana sapphire mines have been less successful because they have few blue sapphires and non-blue sapphires have low profit margins.
These gems inspired the names of features: the mountains near Rock Creek are known as the
Sapphire Mountains
The Sapphire Mountains are a range of mountains located in southwestern Montana in the northwestern United States. From a point near the Clark Fork River and the city of Missoula, they run in a southerly direction for a distance of approximately ...
.
Garnet
Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.
All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different s ...
s are also found at some Montana sapphire sites, inspiring the name of the
Garnet Range
The Garnet Range, highest point Old Baldy Mountain, elevation , is a mountain range northeast of Drummond, Montana in Powell County, Montana.
A popular historic site, Garnet Ghost Town, is in the Garnet Range. Situated on Bureau of Land Manageme ...
, which lies to the north of the Sapphire Mountains. In 1969, the sapphire and
agate
Agate () is a common rock formation, consisting of chalcedony and quartz as its primary components, with a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks. The ornamental use of agate was common in Ancie ...
were jointly declared Montana's two official
state gemstones.
History
![A Quiet Day In Utica - CMRussell](https://upload.wikimedia.org/wikipedia/commons/c/cd/A_Quiet_Day_In_Utica_-_CMRussell.jpg)
Mining of Yogo sapphires was exceptionally difficult and remains sporadic today. Even so, Yogo sapphire mining turned out to be more valuable than several gold strikes. The Yogo area also produced small amounts of silver, copper, and iron.
Yogo Gulch lies in a region originally inhabited by the Piegan Blackfeet people. Gold was first discovered at Yogo Creek in 1866, but the small numbers of early prospectors were driven off by local
Native Americans. During a
Gold Rush
A gold rush or gold fever is a discovery of gold—sometimes accompanied by other precious metals and rare-earth minerals—that brings an onrush of miners seeking their fortune. Major gold rushes took place in the 19th century in Australia, New Z ...
in 1878, about a thousand miners came to Yogo Creek, which was one of the gold-bearing streams in Montana not yet actively mined. "Blue pebbles" were noted along with small quantities of gold. The mining camp at Yogo City only flourished for roughly three years, and eventually the population dwindled to only a few people.
Yogo City was briefly known as Hoover City, after Jake Hoover. Hoover was part of a partnership that had been
placer mining
Placer mining () is the mining of stream bed (Alluvium, alluvial) deposits for minerals. This may be done by open-pit mining, open-pit (also called open-cast mining) or by various surface excavating equipment or tunneling equipment.
Placer minin ...
for gold and is credited as the discoverer of Yogo Sapphires. For several years, he also owned a ranch in nearby Pig-Eye Basin. He later prospected for gold in
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
and was a deep-sea fishing guide in
Seattle
Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...
before eventually returning to the Judith Basin. Western painter
C.M. Russell
Charles Marion Russell (March 19, 1864 – October 24, 1926), also known as C. M. Russell, Charlie Russell, and "Kid" Russell, was an American artist of the American Old West. He created more than 2,000 paintings of cowboys, Native Americans, an ...
arrived in the area in 1880 as a young cowhand and was hired by Hoover. Russell stated that he learned most of his frontier skills from Hoover, and the two men remained lifelong friends. Millie Ringold, a former slave born in 1845, settled in
Fort Benton, Montana
Fort Benton is a city in and the county seat of Chouteau County, Montana, United States. Established in 1846, Fort Benton is the oldest continuously occupied settlement in Montana. The city's waterfront area, the most important aspect of its 1 ...
after having worked as a nurse and servant for an army general. When gold was discovered at Yogo Creek, Ringold sold her boarding house in Fort Benton and left for the Yogo gold fields, setting up a hotel, restaurant, and saloon in Yogo City where she sang and played music. Ringold later cooked for the English mine, but also worked her own gold claims, even after gold mining was on the decline. She was known as a superb cook and ultimately died in Yogo City in 1906, the last resident of the community. The nearby town of Utica was featured in Russell's 1907 painting ''A Quiet Day In Utica'', which was originally known as ''Tinning a Dog''. Hoover, Ringold, store owner Charles Lehman, and Russell himself are all depicted in the painting, placed between the hitching post and door of the general store.
Discovery
![YogoPeakP318](https://upload.wikimedia.org/wikipedia/commons/9/98/YogoPeakP318.jpg)
In 1894, the "blue pebbles" were recognized as sapphires. One story credits a local school teacher for recognizing the blue pebbles as sapphires. A variation is that the teacher lived in Maine, but was a friend of a local miner, who had mailed her a small box with some gold and a few "blue pebbles" in it. Another story credits a miner named S.S. Hobson for surmising that the blue stones might be sapphires, and his guess was confirmed by a jeweler in Helena. Ultimately, in 1895, Jake Hoover sent a cigar box containing those he had collected while mining gold to an assay office, which in turn sent them via regular, uninsured mail to Tiffany's in New York City for appraisal by Dr.
George Frederick Kunz
George Frederick Kunz (September 29, 1856 – June 29, 1932) was an American mineralogist and mineral collector.
Biography
Kunz was born in Manhattan, New York City, USA, and began an interest in minerals at a very young age. By his teens, he ...
, the leading American gemologist of the time. Impressed by their quality and color, Kunz pronounced them "the finest precious gemstones ever found in the United States". Tiffany's sent Hoover a check for $3,750 (approximately $ as of ), along with a letter that described the blue pebbles as "sapphires of unusual quality".
Early mining
Yogo sapphires were ultimately traced from the alluvium to their source. In February 1896, a sheepherder named Jim Ettien found the sapphire
mother lode: the Yogo dike. Ettien was prospecting for gold, and found sapphires after washing gravel he found in a fissure within a limestone outcrop. Ettien staked two claims. The vein turned out to be long and several other miners promptly staked claims along it. Ettien sold his claims to Hoover; Hoover in turn sold his interest in eight original mining stakes, known as the "New Mine Sapphire Syndicate", to his two partners for $5,000 (approximately $ as of ). This site was from Yogo City. In 1899, Johnson, Walker and Tolhurst, Ltd. of London purchased the New Mine Sapphire Syndicate for $100,000 (approximately $ million as of ). At that point, the operation became unofficially known as the "English Mine".
On July 4, 1896, two other Americans, John Burke and Pat Sweeney, staked six mining claims on the western portion of the Yogo dike—areas Hoover had deemed unfit for mining. These claims were collectively known as the "Fourth of July Claim", and became known as the "American Mine". In 1904, the mine was bought by the American Gem Syndicate, and it sold in 1907 to the American Sapphire Company.
![YogoFace1897P456](https://upload.wikimedia.org/wikipedia/commons/0/01/YogoFace1897P456.jpg)
One of the Englishmen who came to the area was Charles Gadsden of
Berkhamsted
Berkhamsted ( ) is a historic market town in Hertfordshire, England, in the Bulbourne valley, north-west of London. The town is a civil parish with a town council within the borough of Dacorum which is based in the neighbouring large new town ...
,
Hertfordshire
Hertfordshire ( or ; often abbreviated Herts) is one of the home counties in southern England. It borders Bedfordshire and Cambridgeshire to the north, Essex to the east, Greater London to the south, and Buckinghamshire to the west. For govern ...
. By 1902, Gadsden was promoted to resident supervisor of the English Mine, and he quickly turned its focus from gold to sapphires. Gadsden's security measures were very tight, as weight-for-weight, rough sapphires were and continue to be worth much more than gold. The English Mine flourished until the 1920s, but floods on July 26, 1923, so severely damaged the mines that they never fully recovered. Between the aftermath of flooding and hard economic times, the English Mine finally failed in 1929. It had recovered more than of rough sapphires that produced of finished gems valued at $25 million in 1929 dollars (approximately $ million as of ). A series of other firms mined sapphires there, but with marginal success. For much of the 1930s and 1940s Gadsden worked the mine alone and used his own money to pay its property taxes. He remained caretaker of the mines until shortly before his death on March 11, 1954.
The American Mine operations were less profitable than those of the English Mine. While the English Mine used superior mining and management techniques on a richer lode, the American Mine suffered from insufficient space and lack of water for ore weathering. Roughs from the English Mine were shipped to London and sold in Europe, often with claims they were sapphires from the Far East, while the American Mine had difficulty marketing its gems within the United States. The American Sapphire Company, which used local
gemcutter
Lapidary (from the Latin ) is the practice of shaping stone, minerals, or gemstones into decorative items such as cabochons, engraved gems (including cameos), and faceted designs. A person who practices lapidary is known as a lapidarist. A lap ...
s from
Great Falls
Great may refer to: Descriptions or measurements
* Great, a relative measurement in physical space, see Size
* Greatness, being divine, majestic, superior, majestic, or transcendent
People
* List of people known as "the Great"
*Artel Great (born ...
, went bankrupt in 1909; a new firm, the Yogo American Sapphire Company, bought the American Mine, but was bankrupt by 1913. Gadsden and his wife had convinced the New Mine Sapphire Syndicate to buy out the Yogo American Sapphire Company in 1914, and in doing so, the English syndicate gained control of all known Yogo deposits. They quickly recouped the purchase price by washing the
tailings
In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different to overburden, which is the waste rock or other material that overlie ...
left behind by previous operators of the American Mine.
1940s–1970s
![YogoMine1897P456](https://upload.wikimedia.org/wikipedia/commons/4/4e/YogoMine1897P456.jpg)
Montana sapphires were heavily mined during for industrial abrasive and cutting purposes. As the Yogo mines were still owned by the English, the United States government could not control those operations, so the mines were little affected by the war, even though industrial sapphires were critical to the war effort. The Yogo Sapphire Mining Corporation of
Billings, Montana
Billings is the largest city in the U.S. state of Montana, with a population of 117,116 as of the 2020 census. Located in the south-central portion of the state, it is the seat of Yellowstone County and the principal city of the Billings Metrop ...
, was the next company to try to run the English Mine. They made an initial offer in 1946, and reached a deal by 1949, but the purchase was not complete until 1956 because of legal issues. The sale was finally completed for $65,000 cash and some stock considerations because the company's capital was exhausted, similar to previous Yogo ventures. The Yogo Sapphire Mining Corporation then changed its name to be the same as the former English firm's name: New Mine Sapphire Syndicate. It became informally known as the "American Syndicate" to distinguish it from the previous "English Syndicate". Production was poor and mining ceased in September 1959. From 1959 to 1963, the mine itself was left unattended and unsecured, resulting in hobbyists, picnickers, and
rockhounds' coming from all over the US and Canada to gather loose rough sapphires. The American Syndicate took action to stop this in 1963, with fences and threats of prosecution. The American Syndicate then tried leasing the mine to several operators. One of these was Siskon, Inc. of Nevada, which lost a significant amount of money. They sued, and in May 1965 the Montana Supreme Court ruled in Siskon's favor. Siskon bought the mine at a sheriff's sale and in turn leased it to a group headed by Arnold Baron, who had a background in gemcutting and jewelry. Baron organized German and
Thai
Thai or THAI may refer to:
* Of or from Thailand, a country in Southeast Asia
** Thai people, the dominant ethnic group of Thailand
** Thai language, a Tai-Kadai language spoken mainly in and around Thailand
*** Thai script
*** Thai (Unicode block ...
gemcutters and had success in marketing Yogo sapphires in America—the first such success in 50 years. However, owing to the difficulty in mining the hard rock site, he did not exercise his option to buy the mine, and Siskon sold it in August 1968 to Herman Yaras of
Oxnard, California
Oxnard () is a city in Ventura County, California, United States. On California's South Coast, it is the most populous city in Ventura County and the 22nd-most-populous city in California. Incorporated in 1903, Oxnard lies approximately west ...
, for $585,000.
![YogoDikeP420](https://upload.wikimedia.org/wikipedia/commons/0/0b/YogoDikeP420.jpg)
In 1969, Yaras' Sapphire Village, Inc. created the Sapphire Village, a nearby homesite development offering buyers limited mining rights to gather their own sapphires with hand tools. Having done no significant mining or marketing, Sapphire Village, Inc. sold in 1973 to one of its investors, Chikara Kunisaki, a celery farmer from Oxnard, California. Kunisaki renamed the business Sapphire International Corporation and attempted to create a commercial mining operation. He built a modern tunnel at the site of the old American Mine, named the "Kunisaki Tunnel". But operation costs were so high that Sapphire International Corporation shut down in late 1976. This was the last actual attempt to mine the American Mine section of the Yogo dike, and today, only the locked portal to the tunnel still exists.
In January 1977, Victor di Suvero and his firm Sapphire-Yogo Mines became the next owner to tackle the Yogo dike. Di Suvero was a native-born Italian who grew up in
Tientsin, China
Tianjin (; ; Mandarin: ), alternately romanized as Tientsin (), is a municipality and a coastal metropolis in Northern China on the shore of the Bohai Sea. It is one of the nine national central cities in Mainland China, with a total popula ...
, and had been successful with a
jade
Jade is a mineral used as jewellery or for ornaments. It is typically green, although may be yellow or white. Jade can refer to either of two different silicate minerals: nephrite (a silicate of calcium and magnesium in the amphibole group of ...
mine in California. Di Suvero's expertise was in marketing: he formed a company called Sapphire Trading to cut and market the Yogo sapphires. He had novel marketing ideas but was not knowledgeable about the mining side of the business. Unable to make payments, his venture folded in late 1979.
By 1980, only four American owners had been successful at Yogo Gulch, all early in its mining history. The English syndicate had been the most profitable of any venture, and even that venture was short-lived. At least thirteen American-owned Yogo mining efforts had failed. Besides inherent difficulties with financing and the challenges of hard rock mining, the American owners generally did not understand how to effectively market the gems.
1980s and beyond
Kunisaki put his mine up for sale, asking $6 million to recoup his expenses. Even though mine profits had been poor over the decades, prices of precious gems were very high at the time due to the worldwide oil crises of the 1970s and early 1980s. Four individuals or groups seriously considered Kunisaki's offer. Relying heavily upon Delmer Brown's expertise, Harry C. Bullock and J. R. Edington formed the limited partnership American Yogo Sapphire Limited, becoming the 14th American company to work the Yogo dike. Bullock and Brown had Yogo mine experience, as they had worked with di Suvero. Bullock's plan included mining, cutting, making jewelry, and marketing—the whole spectrum of the business. They paid the $6 million asked by Kunisaki and then raised another $7.2 million in funding by October 1981. Brown located quality gemcutters in Thailand, and set up the American Yogo Sapphire Company there. Brown also set up a thorough, computerized security system that tracked gems from the mine to the gemcutters. Bigger roughs were sent to American cutters, specialty cuts were done in Germany, a few cuts were done in Hong Kong, and the vast majority were done in Thailand. American Yogo Sapphire Limited secured a $5 million line of credit with
Citibank
Citibank, N. A. (N. A. stands for " National Association") is the primary U.S. banking subsidiary of financial services multinational Citigroup. Citibank was founded in 1812 as the City Bank of New York, and later became First National City ...
. Desiring a more modern name, American Yogo Sapphire Limited changed its name to Intergem Limited in early 1982. Intergem marketed the Yogo as the "Royal American Sapphire." Their first line of jewelry appeared in mid-1982, first marketed regionally in the American west and later at the national level. Intergem also developed a system of authorized dealers, and found success in its first four years, with sales over $3 million in 1984 alone.
![Thai Gem Cutting](https://upload.wikimedia.org/wikipedia/commons/3/33/Thai_Gem_Cutting.jpg)
Intergem rocked the gem trade by marketing the Yogo as the world's only guaranteed untreated sapphire. By 1982, the practice of routinely heat treating gems had become a major issue in the industry. At the time, 95 percent of all the world's sapphires were being heated to enhance their natural color. Thai traders had even purchased large quantities of naturally colorless Sri Lankan sapphires, known as
geuda
Geuda (, pronounced gay-yoo-dah) is a form of the mineral corundum, or sapphire, found primarily in Sri Lanka. Around 70%-80% of gems mined in Sri Lanka belong to geuda varieties. Because of its semitransparent and milky appearance due to rutile ...
, and heated them to turn them into a marketable range of blue colors. Intergem's marketing of guaranteed untreated Yogo sapphires set them against many in the gem industry. In 1985 there was a movement in Pennsylvania to require disclosure that a gem had been treated. Intergem's strategy resulted in large numbers of gem professionals visiting Yogo Gulch.
Intergem began planning to dig even deeper into the Yogo dike, which held more known reserves than all the world's other known sapphire deposits combined, albeit deep underground rather than near the surface in the manner of the other known deposits. They also set up a washing plant and maintenance sheds at the site of the former American mine. Intergem had made a $1.5 million down payment and agreed to make semi-annual payments to Kunisaki's Sapphire International Corporation, which had been renamed to Roncor. Intergem also had loan and interest payments on the $7.2 million loan to make to Citibank. While the company's sales were steadily increasing, their profits were still too low and in May 1985 they missed a $250,000 payment to Roncor. Simultaneously, their collateral of gems, held by Citibank, declined because the value of their collateral was declining; as a result, Citibank called in its loan. Intergem had over $1 million in sales lined up for the 1985 Christmas season, but could only fill a tiny portion because they did not have enough operating capital to manufacture the Yogo jewelry. In mid-1986, Roncor regained full ownership even though Intergem had sold loose gems and jewelry worth millions of dollars.
Various companies attempted to lease the mine from Roncor, but in the meantime, two local couples, Lanny and Joy Perry and Chuck and Marie Ridgeway, discovered a new site at Yogo Gulch in January 1984 by following a trail to an unused section of the dike that had previously been deemed unsuitable. They began mining the site and named it the "Vortex Mine", forming a company named Vortex Mining. The mine shaft was deep and contained two Yogo ore-bearing veins. The portion of the dike they had mined was an extension of the main dike. The Vortex Mine, renamed Yogo Creek Mining, was successful for years but eventually declined and closed in 2004.
![Point-19 carat diamond cut blue Yogo sapphireCROP](https://upload.wikimedia.org/wikipedia/commons/b/b8/Point-19_carat_diamond_cut_blue_Yogo_sapphireCROP.jpg)
In 1992, Roncor found an rough. AMAX Exploration, operating as the Yogo Sapphire Project, signed a 22-month lease with Roncor in March 1993 and had some success in the middle and eastern portions of the dike; it decided not to continue after the end of its lease due to the cost of underground mining, depletion of easily accessible Yogo sapphires, and the relatively small size of Yogo sapphires then easily accessible. During this time, additional dikes were found in the area using
geophysical
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som ...
magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
surveys. Low-grade sapphire rough was found in the Eastern Flats Dike, a parallel dike some 500 feet northeast of the main dike. Pacific Cascade Sapphires, a Canadian company, had a mining lease with Roncor in 2000 and 2001 but ran out of funds and their option expired. By this time, most of the easily accessible Yogo sapphires had been mined and miners had to dig deeper, further increasing costs.
In 1995, Intergem's stock of gems began to reappear on the market because the company had paid its salesmen in sapphires during its financial demise. After Intergem collapsed, many of its salesmen continued to sell Yogo sapphires, especially after AMAX ceased operations. Citibank also had obtained a large stock of Yogo sapphires, reputedly worth $3.5 million (approximately $ as of ), as a result of Intergem's collapse: of rough, of cut gems, and 2,000 pieces of jewelry, all of which sat in the bank's vaults until 1991 when Sofus Michelsen, director of the Center for Gemstone Evaluation and creator of the ''Michelsen Gemstone Index'', became interested. In 1992, he and Jim Adair, a
Missoula, Montana
Missoula ( ; fla, label=Salish language, Séliš, Nłʔay, lit=Place of the Small Bull Trout, script=Latn; kut, Tuhuⱡnana, script=Latn) is a city in the U.S. state of Montana; it is the county seat of Missoula County, Montana, Missoula Cou ...
, jeweler who is the world's largest retailer of Yogo sapphires, got together, and by October 1994 Adair had purchased Citibank's four sealed bags of Yogo material. However, only one of the bags was truly valuable. Adair and Michelsen designed custom cutting techniques for Yogo sapphires.
A new owner, Michael Duane Roberts, bought the Vortex Mine in 2008. Its operations were designed to be environmentally friendly, using methods such as recycling all water and not using other chemicals. Roberts died in a mining accident in 2012. , there was also mining activity by individual hobby miners on small parcels at Sapphire Village, but the Roncor mines remained inactive. In 2017, Vortex Mines was sold to Don Baide who plans to continue operations.
Notable specimens
![Detail - Conchita Sapphire Butterfly head with Yogo sapphire crop - 2011-01-07](https://upload.wikimedia.org/wikipedia/commons/b/b4/Detail_-_Conchita_Sapphire_Butterfly_head_with_Yogo_sapphire_crop_-_2011-01-07.jpg)
Several Yogo sapphires are kept at the
Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...
. The earliest donations were noted in the museum's annual report on June 30, 1899, when the institution reported that Dr. L. T. Chamberlain gave them two cut Yogo sapphires and 21 other sapphires for their Dr.
Isaac Lea
Isaac; grc, Ἰσαάκ, Isaák; ar, إسحٰق/إسحاق, Isḥāq; am, ይስሐቅ is one of the three patriarchs of the Israelites and an important figure in the Abrahamic religions, including Judaism, Christianity, and Islam. He was the ...
gem and mineral collection. The record-setting cut Yogo is also held by the Smithsonian. In 2006, gemologist Robert Kane of Fine Gems International in Helena, donated 333 Montana sapphires, weighing a total of , to the
Smithsonian's Gem and Mineral Collection, along with 98.48 grams of 18K yellow gold for the creation of a piece of jewelry. A representative of the Smithsonian asked Paula Crevoshay, a jewelry designer from
Albuquerque, New Mexico
Albuquerque ( ; ), ; kee, Arawageeki; tow, Vakêêke; zun, Alo:ke:k'ya; apj, Gołgéeki'yé. abbreviated ABQ, is the most populous city in the U.S. state of New Mexico. Its nicknames, The Duke City and Burque, both reference its founding in ...
, to create a piece of finished jewelry from these gems. Crevoshay felt that a butterfly motif would best represent America's natural beauty, honor her mother's love of butterflies, and display the wide range of colors found in Montana sapphires. Crevoshay named the brooch "Conchita" in honor of her mother; it is also referred to as the "Sapphire Butterfly Brooch", "Conchita Sapphire Butterfly", and the "Montana Butterfly Brooch". Two of the sapphires used are
cabochon
A cabochon (; ) is a gemstone that has been shaped and polished, as opposed to faceted. The resulting form is usually a convex (rounded) obverse with a flat reverse. Cabochon was the default method of preparing gemstones before gemstone cuttin ...
cut and the rest are brilliant cut. The majority are from the Rock Creek deposit. The largest one, however, is a blue Yogo used for the butterfly's head. Other sapphires used included yellow, purple, pink, and orange gems. Crevoshay completed the brooch in 2007; she and Kane presented the finished brooch to Smithsonian curator Jeffrey Post on May 7, 2007, in Washington, DC.
![Tiffany and Company Iris Corsage Ornament Walters 57939 Detail croped](https://upload.wikimedia.org/wikipedia/commons/4/44/Tiffany_and_Company_Iris_Corsage_Ornament_Walters_57939_Detail_croped.jpg)
In the earliest years of Yogo sapphire mining, before Yogo sapphires achieved their own reputation, Oriental sapphires were sold in Montana with claims they were Yogo sapphires, while in Europe, Yogo sapphires were sold as Oriental sapphires. However, Yogo sapphires became notable in their own right.
Paulding Farnham
George Paulding Farnham (1859–1927) was an American jewelry designer, sculptor and metallurgist who worked for Tiffany & Co. in the late 19th and early 20th century. Farnham married American sculptor Sally James Farnham in 1896. After leaving ...
(1859–1927) used Yogo sapphires in several jewelry pieces he designed for the
1900 Exposition Universelle in Paris, where Yogo sapphires received a silver medal among all gems for color and clarity. An entry of uncut loose Yogo sapphires also won a bronze medal at the
1904 Louisiana Purchase Exposition in
St. Louis, Missouri
St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi River, Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the Greater St. Louis, ...
. Farnham was the creator of the most elaborate piece of jewelry ever made with Yogo sapphires, the life-size Tiffany Iris Brooch, a brooch ornament, which contains 120 Yogo sapphires set in platinum, and sold on March 17, 1900, for $6,906.84. In 1923,
First Lady
First lady is an unofficial title usually used for the wife, and occasionally used for the daughter or other female relative, of a non-monarchical
A monarchy is a form of government in which a person, the monarch, is head of state fo ...
Florence Harding
Florence Mabel Harding (née Kling; August 15, 1860 – November 21, 1924) was the first lady of the United States from 1921 until her husband's death in 1923 as the wife of President Warren G. Harding.
Florence first married Pete De Wolfe ...
was given an "all Montana" ring made from a Yogo sapphire and Montana gold. In 1952, Gadsden gave cut Yogo sapphires to
President Harry Truman
Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. A leader of the Democratic Party, he previously served as the 34th vice president from January to April 1945 under Franklin ...
, his wife
Bess, and their daughter
Margaret
Margaret is a female first name, derived via French () and Latin () from grc, μαργαρίτης () meaning "pearl". The Greek is borrowed from Persian.
Margaret has been an English name since the 11th century, and remained popular througho ...
. Many Yogo sapphires were also sold in Europe, as some Yogo mining was conducted by British interests. Yogo sapphires may have been in the personal collections of some members of the British royal family in the 1910s, but promotional claims that Yogo sapphires are in any of the crown jewels of England cannot be conclusively proven or disproven. Claims that the gem in the engagement ring of
Lady Diana Spencer
Diana, Princess of Wales (born Diana Frances Spencer; 1 July 1961 – 31 August 1997) was a member of the British royal family. She was the first wife of King Charles III (then Prince of Wales) and mother of Princes William and Harry. Her ac ...
and
Kate Middleton
Catherine, Princess of Wales, (born Catherine Elizabeth Middleton; 9 January 1982) is a member of the British royal family. She is married to William, Prince of Wales, heir apparent to the British throne, making Catherine the likely next ...
is a Yogo are dubious; the gem is thought to be of Sri Lankan origin. The story that the gem is a Yogo can be traced to a 1984 ''
Los Angeles Times
The ''Los Angeles Times'' (abbreviated as ''LA Times'') is a daily newspaper that started publishing in Los Angeles in 1881. Based in the LA-adjacent suburb of El Segundo since 2018, it is the sixth-largest newspaper by circulation in the Un ...
'' article that described the ring as a sapphire, and quoted Intergem president Dennis Brown's claim that the gem may have come from a British-owned Yogo mine.
See also
*
Bismarck Sapphire Necklace
The Bismarck Sapphire Necklace is a sapphire necklace designed by Cartier, Inc. in 1935. As of 2010, the necklace is on display between the Hall Sapphire and Diamond Necklace and the Logan Sapphire in the Janet Annenberg Hooker Hall of Geology, ...
*
Hall Sapphire and Diamond Necklace
*
Logan sapphire
The Logan Sapphire is a sapphire from Sri Lanka. One of the largest blue faceted sapphires in the world, it was owned by Sir Victor Sassoon and then purchased by M. Robert Guggenheim as a gift for his wife, Rebecca Pollard Guggenheim, who donat ...
Notes
Footnotes
References
*
*
External links
Birth of a Yogo sapphire (photo sequence showing cutting of 7.73 rough to a 2.62 carat finished gem)Development of Montana Sapphire IndustryNew Mine Sapphire Syndicate Records, 1889-1967(University of Montana Archives)
{{DEFAULTSORT:Yogo sapphire
Aluminium minerals
Dielectrics
Corundum gemstones
Geology of Montana
Optical materials
Oxide minerals
Superhard materials
Transparent materials
Trigonal minerals
Minerals in space group 167