![Serpentyn, 2Polska](https://upload.wikimedia.org/wikipedia/commons/7/70/Serpentyn%2C_2Polska.jpg)
Serpentine subgroup (part of the
kaolinite-serpentine group in the category of phyllosilicates)
are greenish, brownish, or spotted minerals commonly found in
serpentinite
Serpentinite is a rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''se ...
. They are used as a source of
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
and
asbestos, and as decorative stone. The name comes from the greenish colour and smooth or scaly appearance from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
, meaning "serpent rock".
Serpentine subgroup is a set of common
rock
Rock most often refers to:
* Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids
* Rock music, a genre of popular music
Rock or Rocks may also refer to:
Places United Kingdom
* Rock, Caerphilly, a location in Wales ...
-forming
hydrous
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
iron
Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
phyllosilicate
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust.
In mineralogy, silica (silicon dioxide, ) is usually consid ...
()
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
s, resulting from the
metamorphism
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ch ...
of the minerals that are contained in
mafic
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks incl ...
to
ultramafic rocks
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are compos ...
. They may contain minor amounts of other elements including
chromium,
manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
,
cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...
or
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...
. In
mineralogy and
gemology
Gemology or gemmology is the science dealing with natural and artificial gemstone materials. It is a geoscience and a branch of mineralogy. Some jewelers (and many non-jewelers) are academically trained gemologists and are qualified to identif ...
, serpentine may refer to any of the 20 varieties belonging to the serpentine subgroup. Owing to admixture, these varieties are not always easy to individualize, and distinctions are not usually made. There are three important mineral
polymorphs of serpentine:
antigorite
Antigorite is a lamellated, monoclinic mineral in the phylosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinite ...
,
lizardite and
chrysotile
Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United StatesOccupational Safety and Health Administration, U.S. Department of Labor (2007)29 C.F.R.&nb ...
.
Serpentine minerals are
polymorphous
Polymorphism, polymorphic, polymorph, polymorphous, or polymorphy may refer to:
Computing
* Polymorphism (computer science), the ability in programming to present the same programming interface for differing underlying forms
* Ad hoc polymorphis ...
, meaning that they have the same
chemical formulae
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...
, but the atoms are arranged into different structures, or
crystal lattices
In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of discrete translation operations described in three dimensional space by
: \mathbf = n_1 \mathbf_1 + n_2 \mathbf_2 + n_ ...
.
Chrysotile
Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United StatesOccupational Safety and Health Administration, U.S. Department of Labor (2007)29 C.F.R.&nb ...
, which has a
fibrous habit, is one polymorph of serpentine and is one of the more important
asbestos minerals. Other polymorphs in the serpentine subgroup may have a
platy habit.
Antigorite
Antigorite is a lamellated, monoclinic mineral in the phylosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinite ...
and
lizardite are the polymorphs with platy habit.
Many types of serpentine have been used for
jewelry
Jewellery ( UK) or jewelry ( U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a w ...
and
hardstone carving
Hardstone carving is a general term in art history and archaeology for the artistic carving of predominantly semi-precious stones (but also of gemstones), such as jade, rock crystal (clear quartz), agate, onyx, jasper, serpentinite, or carneli ...
, sometimes under the name "false jade" or "Teton jade".
[Hunter, Sir William Wilson and Burn, Sir Richard, The Imperial Gazetteer of India, Vol. 3, Oxford, England: Clarendon Press, Henry Frowde Publishers (1907), p. 242]
Properties and structure
![Serpetine chemical structure](https://upload.wikimedia.org/wikipedia/commons/6/61/Serpetine_chemical_structure.png)
Most serpentines are opaque to translucent, light (
specific gravity
Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...
between 2.2 and 2.9), soft (
hardness
In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...
2.5–4), infusible and susceptible to
acids.
All are
microcrystalline
A microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination. There is little agreement on the range of crystal sizes that should be regarded as microcrystalline, but th ...
and massive in
habit
A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously. , never being found as single
crystal
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...
s.
Lustre may be vitreous, silky or greasy. Colours range from white to grey, yellow to green, and brown to black, and are often splotchy or veined. Many are intergrown with other minerals, such as
calcite and
dolomite Dolomite may refer to:
*Dolomite (mineral), a carbonate mineral
*Dolomite (rock), also known as dolostone, a sedimentary carbonate rock
*Dolomite, Alabama, United States, an unincorporated community
*Dolomite, California, United States, an unincor ...
.
The basic structural unit of serpentine is a
polar layer 0.72 nm thick. A
Mg-rich
trioctahedral sheet is tightly linked on one side to a single
tetrahedral silicate sheet, regardless of the 3–5% larger lateral lattice dimensions of the
octahedral sheet. The second level of the structure organized into different serpentine species originates partly to compensate the intra-layer
stress
Stress may refer to:
Science and medicine
* Stress (biology), an organism's response to a stressor such as an environmental condition
* Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
due to this dimensional misfit. Good compensation results in a nearly constant layer
curvature, with the larger octahedral sheet on the convex side. However, such curvature weakens the
H-bonding
In chemistry, a hydrogen bond (or H-bond) is a primarily electrostatic force of attraction between a hydrogen (H) atom which is covalently bound to a more electronegative "donor" atom or group (Dn), and another electronegative atom bearing a ...
between the layers. H-bonding tries to maintain flat layers, but this competes with the requirements of misfit compensation. As a result, the layers are locally either curved or flat.
Antigorite
Antigorite is a lamellated, monoclinic mineral in the phylosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinite ...
,
lizardite and
chrysotile
Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United StatesOccupational Safety and Health Administration, U.S. Department of Labor (2007)29 C.F.R.&nb ...
have the same
chemical composition, but their different layer of curvatures result in lamellar agglomerated antigorite and lizardite and fibrous chrysotile elongated
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
particles.
Occurrence
Serpentine minerals are ubiquitous in many geological systems where hydrothermal alteration of ultramafic rocks is possible, in both terrestrial (oceanic hydrothermalism, subduction zones and transform faulting) and extraterrestrial environments. The process of alteration from
mafic
A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks incl ...
minerals to serpentine group minerals is called
serpentinization
Serpentinization is a hydration and metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock to produce serpentinite. Minerals formed by serpentinization include the serpentine group mine ...
. Serpentine minerals are often formed by the hydration of
olivine
The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
-rich ultramafic rocks at relatively low temperatures (0 to ~600 °C). The chemical reaction turns olivine into serpentine minerals. They may also have their origins in
metamorphic
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, causi ...
alterations of
peridotite and
pyroxene. Serpentines may also
pseudomorph
In mineralogy, a pseudomorph is a mineral or mineral compound that appears in an atypical form (crystal system), resulting from a substitution process in which the appearance and dimensions remain constant, but the original mineral is replaced b ...
ously replace other magnesium silicates. Incomplete alteration causesthe physical properties of serpentines to vary widely.
Antigorite is the
polymorph of serpentine that most commonly forms during metamorphism of wet ultramafic rocks and is stable at the highest temperatures—to over at depths of or so. In contrast, lizardite and chrysotile typically form near the Earth's surface and break down at relatively low temperatures, probably well below . It has been suggested that chrysotile is never stable relative to either of the other two serpentine polymorphs.
Samples of the oceanic crust and uppermost mantle from ocean basins document that
ultramafic
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...
rocks there commonly contain abundant serpentine. Antigorite contains water in its structure, about 13 percent by weight. Hence, antigorite may play an important role in the transport of water into the earth in
subduction zones and in the subsequent release of water to create magmas in
island arc
Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...
s, and some of the water may be carried to yet greater depths.
Occurrence is worldwide, notable localities include
New Caledonia,
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
(
Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
),
US (northern
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
,
Rhode Island
Rhode Island (, like ''road'') is a state in the New England region of the Northeastern United States. It is the smallest U.S. state by area and the seventh-least populous, with slightly fewer than 1.1 million residents as of 2020, but it ...
,
Connecticut
Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its capita ...
,
Massachusetts
Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...
,
Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
and southern
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
),
Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordere ...
,
Britain
Britain most often refers to:
* The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands
* Great Britain, the largest island in the United King ...
(the
Lizard peninsula in
Cornwall
Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...
),
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
,
Greece
Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders ...
(
Thessaly
Thessaly ( el, Θεσσαλία, translit=Thessalía, ; ancient Thessalian: , ) is a traditional geographic and modern administrative region of Greece, comprising most of the ancient region of the same name. Before the Greek Dark Ages, The ...
),
China,
Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
(
Ural Mountains
The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
),
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...
,
Korea
Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...
,
Austria
Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...
(
Styria and
Carinthia),
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
(
Assam
Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...
, and
Manipur
Manipur () ( mni, Kangleipak) is a state in Northeast India, with the city of Imphal as its capital. It is bounded by the Indian states of Nagaland to the north, Mizoram to the south and Assam to the west. It also borders two regions of ...
),
Myanmar
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
(
Burma
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
),
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
,
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the ...
and
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
.
Uses
![Budai in serpentine, height 8 cm arp](https://upload.wikimedia.org/wikipedia/commons/1/12/Budai_in_serpentine%2C_height_8_cm_arp.jpg)
Serpentines find use in industry for several purposes, such as railway ballasts, building materials, and the asbestiform types find use as thermal and electrical insulation (chrysotile
asbestos). The asbestos content can be released into the air when serpentine is excavated and if it is used as a road surface, forming a long-term health hazard by breathing. Asbestos from serpentine can also appear at low levels in water supplies through normal weathering processes, but there is as yet no fully proven health hazard associated with use or ingestion, although the EPA states an increased risk of developing benign intestinal polyps can occur. In its natural state, some forms of serpentine react with carbon dioxide and re-release oxygen into the atmosphere.
The more attractive and durable varieties (all of the antigorite) are termed "noble" or "precious" serpentine and are used extensively as
gem
A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, a ...
s and in
ornamental carvings. The town of
Bhera
Bhera ( pa, ; ur, ) is a city and tehsil of Sargodha District, Punjab province of Pakistan. The city is known for wood-carved items, textiles (such as quilts and khussas), and certain desserts (such as pheonian and pateesa).
The city i ...
in the historic
Punjab province of the
Indian subcontinent
The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
was known for centuries for finishing a relatively pure form of green serpentine obtained from quarries in
Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordere ...
into
lapidary
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 ...
work, cups, ornamental sword hilts, and dagger handles.
This high-grade serpentine ore was known as in
Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
, or 'false jade' in English, and was used for generations by Indian craftsmen for lapidary work.
[Watt, Sir George, ''The Commercial Products of India'', London: John Murray Publishers (1908), p. 561] It is easily carved, taking a good polish, and is said to have a pleasingly greasy feel.
['' The Stone Age Jewels: Serpentine'', retrieved 2 October 2011 ] Less valuable serpentine ores of varying hardness and clarity are also sometimes dyed to imitate
jade.
Misleading synonyms for this material include "Suzhou jade", "Styrian jade", and "New jade".
New Caledonian serpentine is particularly rich in nickel. The
Māori
Māori or Maori can refer to:
Relating to the Māori people
* Māori people of New Zealand, or members of that group
* Māori language, the language of the Māori people of New Zealand
* Māori culture
* Cook Islanders, the Māori people of the C ...
of
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
once carved beautiful objects from local serpentine, which they called , meaning "tears".
The of the
Romans
Roman or Romans most often refers to:
*Rome, the capital city of Italy
* Ancient Rome, Roman civilization from 8th century BC to 5th century AD
*Roman people, the people of ancient Rome
*''Epistle to the Romans'', shortened to ''Romans'', a lette ...
, now known as
verde antique, or verde antic, is a serpentinite
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 ...
popular as a decorative facing stone. In classical times it was mined at
Casambala,
Thessaly
Thessaly ( el, Θεσσαλία, translit=Thessalía, ; ancient Thessalian: , ) is a traditional geographic and modern administrative region of Greece, comprising most of the ancient region of the same name. Before the Greek Dark Ages, The ...
,
Greece
Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders ...
. Serpentinite
marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...
s are also widely used: Green
Connemara marble
Connemara marble or "Irish green" is a rare variety of marble found in Connemara, Ireland with a distinct green colour. It is commonly used as a gemstone and for decorations. Due to its colouration, it is commonly associated with the Irish identi ...
(or 'Irish green marble') from
Connemara
Connemara (; )( ga, Conamara ) is a region on the Atlantic coast of western County Galway, in the west of Ireland. The area has a strong association with traditional Irish culture and contains much of the Connacht Irish-speaking Gaeltacht, ...
,
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
(and many other sources), and red from Italy. Use is limited to indoor settings as serpentinites do not
weather
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmos ...
well.
Potential harm
Soils derived from serpentine are toxic to many
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
s, because of high levels of
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...
,
chromium, and
cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...
; growth of many plants is also inhibited by low levels of
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...
and
phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
and a low ratio of
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
/
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
. The
flora
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' ...
is generally very distinctive, with specialized, slow-growing species. Areas of
serpentine-derived soil will show as strips of
shrubland and open, scattered small
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s (often
conifers) within otherwise
forest
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
ed areas; these areas are called
serpentine barrens.
Antigorite variety
![Antigorite (Var](https://upload.wikimedia.org/wikipedia/commons/e/eb/Antigorite_%28Var._Bowenite%29.jpg)
Lamellated antigorite occurs in tough, pleated masses. It is usually dark green, but may also be yellowish, gray, brown or black. It has a hardness of 3.5–4 and its luster is greasy. The monoclinic crystals show micaceous
cleavage and fuse with difficulty. Antigorite is named after its type locality, the Geisspfad serpentinite,
Valle Antigorio in the border region of
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
/
Switzerland.
Bowenite
Bowenite Bowenite is a hard, compact variety of the serpentinite species antigorite, (Mg3(OH)O4Si2O5). Classed as semi-precious gemstone it has been used for tools, weapons and jewellery by the Māori in New Zealand, and for jewellery by Fabergé. Deposits ...
, a variety of antigorite, is an especially hard serpentine (5.5) of light to dark apple green colour, often mottled with cloudy white patches and darker veining. It is the serpentine most frequently encountered in carving and jewelry. The name 'retinalite' is sometimes applied to yellow bowenite. The New Zealand material is called .
Although not an official species, bowenite is the state mineral of
Rhode Island
Rhode Island (, like ''road'') is a state in the New England region of the Northeastern United States. It is the smallest U.S. state by area and the seventh-least populous, with slightly fewer than 1.1 million residents as of 2020, but it ...
, United States: this is also the variety's type locality. A bowenite
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 cutt ...
featured as part of the "Our Mineral Heritage Brooch", was presented to U.S. First Lady Mrs.
Lady Bird Johnson
Claudia Alta "Lady Bird" Johnson (''née'' Taylor; December 22, 1912 – July 11, 2007) was First Lady of the United States from 1963 to 1969 as the wife of President Lyndon B. Johnson. She previously served as Second Lady from 1961 to 1963 whe ...
in 1967.
Williamsite is an American local varietal name for antigorite that is oil-green with black crystals of
chromite or
magnetite
Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With th ...
often included. Somewhat resembling fine jade, williamsite is cut into cabochons and beads. It is found mainly in
Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
and
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
.
Gymnite
Gymnite is an amorphous form of antigorite. It was originally found in the
Bare Hills of
Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
, and is named from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
, , meaning "bare" or "naked".
State emblem
In 1965, the
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
Legislature designated serpentine (the mineral) as "the official State Rock and lithologic emblem.”
[California Government Code § 425.2; ''see'' ]
Gallery
File:Serpentinite (Deer Lake Peridotite, late Neoarchean; Ropes Gold Mine, Upper Peninsula of Michigan, USA) (16755884589).jpg, upSerpentinite from the Precambrian of Michigan, USA
File:Serpentinite (East Dover Ultramafic Body, Ordovician; roadcut east of East Dover, Vermont, USA) 7.jpg, upSerpentinite from East Dover Ultramafic Body, Ordovician; roadcut east of East Dover, Vermont, USA
File:Antigorite-331868.jpg, upAntigorite from Clay Geo, Unst, Shetland Islands, Scotland, UK
File:Antigorite-339279.jpg, upAntigorite from Lord Brassey Mine, Heazlewood district, Tasmania, Australia
File:Antigorite-519491.png, upSlab of curiously patterned antigorite from the Jeffrey Mine, Quebec, Canada
File:Antigorite (variety Picrolite)-317326.jpg, upPicrolite (antigorite) from Quebec looking in color and form like a bit of celery
File:Antigorite-204046.jpg, upGenthite (antigorite) from Wood's Chrome Mine. The bright green, lustrous antigorite richly covering this specimen has an unusual knobby/bubbly/drusy form.
File:Antigorite (variety Bowenite)-346846.jpg, upBowenite (Antigorite) from Asbestos mine, Thurman Township, Warren County, New York, USA
File:serpentine-bowenite.jpg, Polished slab of bowenite serpentine, a variety of antigorite. Typical cloudy patches and veining are apparent.
File:Turban ornament, North India, Delhi or Jaipur, 18th-19th century, antigorite, gold, pearls, glass - Ethnological Museum, Berlin - DSC01519.JPG, upTurban ornament, North India, Delhi or Jaipur, 18th-19th century, antigorite, gold, pearls, glass - Ethnological Museum, Berlin
File:Bordssurtout med flaskor från 1600-talet gjord av svarvad grön serpentin(stensort) - Skoklosters slott - 93563.tif, Serpentine that has turned green, 17th century
File:Jasper earrings and necklace.jpg, upNecklace and earring set made from semiprecious stones. The spherical green beads are Russian serpentine. Also used are jasper
Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases,Kostov, R. I. 2010. Review on the mineralogical systematics of jasper and related rocks. – Archaeometry Workshop, 7, 3, 209-213PDF/ref> ...
(red) and fluorite
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.
The Mohs sca ...
(blue).
References
External links
Mineral description from Mineral galleries* Evans, Bernard W. (2004). ''The Serpentinite Multisystem Revisited: Chrysotile is Metastable.'' In: International Geology Review, v. 46, pages 479–506
* Myron G. (2003). ''Igneous and Metamorphic Petrology, 2nd edition''. Blackwell Publishing.
* Kruckeberg, Arthur R. (2002). ''Geology and Plant Life: the Effects of Landforms and Rock Types on Plants.'' Seattle: University of Washington Press.
{{DEFAULTSORT:Serpentine Group
*
Iron(II) minerals
Magnesium minerals
Symbols of California