Chrysocolla ( ) is a hydrated

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

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 ...

and mineraloid with formula (x<1) or . The structure of the mineral has been questioned, as a 2006 spectrographic study suggest material identified as chrysocolla may be a mixture of the copper hydroxide

spertiniite Spertiniite is a rare copper hydroxide mineral. Chemically it is copper(II) hydroxide with formula Cu(OH)2. It occurs as blue to blue green tabular orthorhombic crystal aggregates in a secondary alkaline environment altering chalcocite. Associa ...

and

chalcedony Chalcedony ( , or ) is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monocli ...

History

The name comes from the

ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

χρυσός (''chrysos'') and κολλα (''kolla''), "gold" and "glue," in allusion to the name of the material used to solder

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...

and was first used by

Theophrastus Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Botany'', Routle ...

in 315 BC.

Geology

Chrysocolla has a cyan (blue-green) color and is a minor ore of copper, having a

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 ...

of 2.5 to 7.0. It is of secondary origin and forms in the

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...

zones of copper

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

bodies. Associated minerals are

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

, limonite,

azurite Azurite is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France. The mineral, a basic carb ...

malachite Malachite is a copper carbonate hydroxide mineral, with the formula Cu2CO3(OH)2. This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fracture ...

cuprite Cuprite is an oxide mineral composed of copper(I) oxide Cu2O, and is a minor ore of copper. Its dark crystals with red internal reflections are in the isometric system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, ...

, and other secondary copper minerals. It is typically found as

botryoidal A botryoidal ( ) texture or mineral habit, is one in which the mineral has an external form composed of many rounded segments, named for the Ancient Greek (), meaning "a bunch of grapes".Adjective form: ''botruoeidēs'' This is a common form f ...

or rounded masses and crusts, or vein fillings. A 2006 study has produced evidence that chrysocolla may be a microscopic mixture of the copper hydroxide mineral

, amorphous silica and water.François Farges, Karim Benzerara, Gordon E. Brown, Jr.; ''Chrysocolla Redefined as Spertiniite''; SLAC-PUB-12232; 13th International Conference On X-Ray Absorption Fine Structure (XAFS13); July 9-14, 2006; Stanford, California
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Jewelry

Due to being somewhat more common than

turquoise Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula . It is rare and valuable in finer grades and has been prized as a gemstone and ornamental stone for thousands of year ...

, its wide availability, and vivid, beautiful blue and blue-green colors, chrysocolla has been popular for use as a gemstone for carvings and ornamental use since antiquity. It is often used in

silversmithing A silversmith is a metalworker who crafts objects from silver. The terms ''silversmith'' and ''goldsmith'' are not exactly synonyms as the techniques, training, history, and guilds are or were largely the same but the end product may vary grea ...

and

goldsmithing A goldsmith is a metalworker who specializes in working with gold and other precious metals. Nowadays they mainly specialize in jewelry-making but historically, goldsmiths have also made silverware, platters, goblets, decorative and serviceable ...

in place of turquoise and is relatively easy to work and shape. Chrysocolla exhibits a wide range of

Mohs hardness 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 t ...

ranging from 2 through 7, which is dependent on the amount of silica incorporated into the stone when it is forming. Generally, dark navy blue chrysocolla is too soft to be used in jewelry, while cyan, green, and blue-green chrysocolla can have a hardness approaching 6, similar to turquoise. Chrysocolla chalcedony is a heavily silicified form of chrysocolla that forms in quartz deposits and can be very hard and approach a hardness of 7.

Gallery

Chrysocolla-Tyrolite-Clinotyrolite-202106.jpg, Powder-blue chrysocolla as stalactitic growths and as a thin carpet in vugs inside a boulder of nearly solid

tyrolite Tyrolite is a hydrated calcium copper arsenate carbonate mineral with formula: Ca Cu5( As O4)2 CO3(O H)4·6 H2O. Tyrolite forms glassy blue to green orthorhombic radial crystals and botryoidal masses. It has a Mohs hardness of 1.5 to 2 and a spe ...

from the San Simon Mine,

Iquique Province Iquique Province ( es, Provincia de Iquique) is one of two provinces in the northern Chilean region of Tarapacá. Its capital is the port city of Iquique. History Until October 2007, the Province of Iquique was composed of 7 communes: Alto Hospi ...

, Chile (size: 14.1 x 8.0 x 7.8 cm) Chrysocolla-201585.jpg, Banded white to blue green chrysocolla from

Bisbee, Arizona Bisbee is a city in and the county seat of Cochise County in southeastern Arizona, United States. It is southeast of Tucson and north of the Mexican border. According to the 2020 census, the population of the town was 4,923, down from 5,575 ...

(size: 12.2 x 5.5 x 5.2 cm) Chrysocolla-bolo.jpg, Chrysocolla and Silver

Bolo Tie A bolo tie (sometimes bola tie or shoestring necktie) is a type of necktie consisting of a piece of cord or braided leather with decorative metal tips (called aiguillettes) and secured with an ornamental clasp or slide. Popularity In the United ...

. This chrysocolla specimen is from the Kennecot Copper Mine in Bingham Canyon,

West Valley City, Utah West Valley City is a city in Salt Lake County and a suburb of Salt Lake City in the U.S. state of Utah. The population was 140,230 at the 2020 census, making it the second-largest city in Utah. The city incorporated in 1980 from a large, quic ...

References

{{Jewellery Copper ores Phyllosilicates Orthorhombic minerals Gemstones

History

Geology

Jewelry

Gallery

See also

References