The Mineral chrysocolla
Chrysocolla is a sharply colored mineral. Its color can be among the brightest shade of blue and green, and is caused by its copper content. Chrysocolla is often coated by a drusy layer of glossy clear Quartz, or intergrown together with the Quartz.
The chemical formula for Chrysocolla is not clearly defined, as it contains a varying substitution of elements and water content in its chemical structure. Though a more definitive form of Chrysocolla with an identifiable chemical formula can exist in microcrystals, most forms are considered amorphous. Multiple analyses of different compositions have been offered over the years.
For additional information, see the gemstone section on Chrysocolla.
Bright green, bluish-green, sky blue, gray. May be mottled or multicolored green and blue.
White to pale blue
2 - 4
Translucent to Opaque
2.0 - 2.2
Vitreous to greasy
Conchoidal to uneven
Basic copper silicate, often with some aluminum. The composition of this mineral is usually variable and it therefore lacks a definitive chemical composition.
Bright color, hardness, and habits
As a secondary alteration mineral in the oxidation zone of copper deposits, hydrothermal replacement deposits, and in igneous rocks.
Igneous, Sedimentary, Metamorphic
Chrysocolla is used as a minor gemstone and may be fashioned into beads and cabochons. It is also occasionally faceted into other gemstone forms for collectors. Although Chrysocolla's colors is very unique and attractive, its low hardness limits its use as a gemstone. The gemstone forms are associated with harder Quartz and are also more stable.
Chrysocolla occurs in many important copper deposits, and is an ore of copper.
Most Chrysocolla is from copper deposits in arid regions, though it is not at all limited to these regions and is found worldwide. Outstanding Chrysocolla in reniform blobs and thick crusts comes from Kolwezi, Katanga (Shaba), Congo (Zaïre). The ancient Timna Copper Mines of Eilat, Israel, have produced Chrysocolla combined with other copper minerals in a combination that has been given the trade name Eilat Stone. Excellent Chrysocolla pseudomorphs after Azurite come from the Whim Creek Copper Mine, Whim Creek, Western Australia. Important South American localities include the Lily Mine, Pisco Umay, Peru; and several deposits within Chañaral Province, Atacama Region, Chile.
The most outstanding Chrysocolla has come from many of the classic Arizona copper mines. The most noteworthy and outstanding are the Inspiration Mine, Globe-Miami District, Gila Co.; the 79 Mine, Hayden, Gila Co.; Morenci, Greenlee Co.; and Ray, Pinal Co. The locality of Ray is especially noted for its beautiful and intriguing stalagmites combined with Quartz.
Distingushing Similar Minerals
Variscite - Usually greener in color.
Turquoise - Harder.
Blue and green Chalcedony - Much harder.
Allophane - Can be very difficult to distinguish.
Smithsonite - Slightly harder and usually lighter in color; otherwise may be difficult to distinguish.