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 pinkish ...

phyllosilicate mineral and

mineraloid A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an am ...

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 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 monocl ...

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 ...

and was first used by Theophrastus in 315 BC.

Geology

Chrysocolla has a cyan (blue-green) color and is a minor ore of copper, having a hardness 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 bodies. Associated minerals are quartz,

limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...

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 car ...

, malachite, cuprite, and other secondary copper minerals. It is typically found as botryoidal 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 spertiniite, 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, 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 and goldsmithing in place of turquoise and is relatively easy to work and shape. Chrysocolla exhibits a wide range of Mohs hardness 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 In crystallography, the orthorhombic crystal system is one of the 7 crystal sys ...

from the San Simon Mine, Iquique Province, Chile (size: 14.1 x 8.0 x 7.8 cm) Chrysocolla-201585.jpg, Banded white to blue green chrysocolla from Bisbee, Arizona (size: 12.2 x 5.5 x 5.2 cm) Chrysocolla-bolo.jpg, Chrysocolla and Silver Bolo Tie. This chrysocolla specimen is from the Kennecot Copper Mine in

Bingham Canyon The Bingham Canyon Mine, more commonly known as Kennecott Copper Mine among locals, is an open-pit mining operation extracting a large porphyry copper deposit southwest of Salt Lake City, Utah, in the Oquirrh Mountains. The mine is the largest m ...

, West Valley City, Utah

References

{{Jewellery Copper ores Phyllosilicates Orthorhombic minerals Gemstones

History

Geology

Jewelry

Gallery

See also

References