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Friday, December 9, 2016

Chrysocolla Gemstone

What is Chrysocolla?

Chrysocolla is a gemstone with a beautiful sky blue to bluish-green colour. Copper in its chemical structure is responsible for the bright attractive colour. It is often multicoloured with inclusions or veining of black and brown matrix material. Chrysocolla's lack of widespread gem use is due to its low hardness and lack of durability. It is sometimes coated or admixed with harder Quartz, and these harder, more solid forms are better fit for gemstone use.

Name and discovery

The name comes from the Ancient Greek, "gold glue", in allusion to the name of the material used to solder gold, and was first used by Theophrastus in 315 BCE.

Formation and occurrence

It is of secondary origin and forms in the oxidation zones of copper ore bodies. Associated minerals are quartz, limonite, azurite, malachite, cuprite, and other secondary copper minerals.
It is typically found as botryoidal or rounded masses and crusts, or vein fillings. Because of its light colour, it is sometimes confused with turquoise.
Notable occurrences include Bacan Island Indonesia, Israel, Democratic Republic of Congo, Chile, Cornwall in England, and Arizona, Utah, Idaho, New Mexico, Michigan, and Pennsylvania in the United States.

Chrysocolla Gemstone Properties

Chemical FormulaCu2H2Si2O5(OH)4
ColourBlue, Green, Multicolored
Hardness2 - 4
Crystal SystemOrthorhombic
Refractive Index1.4 - 1.6
SG2.0 - 2.2
TransparencyOpaque
Double RefractionNone
LusterVitreous to greasy
CleavageNone
Mineral ClassChrysocolla