Azurite

Azurite

 

Formula: Cu3(CO3)2(OH)2

Azurite is a member of the carbonate group.

It is also known as Chessylite after the type locality at Chessy-les-Mines near Lyon, France.

Azurite is a soft, deep blue copper mineral produced by weathering of copper ore deposits. The mineral, a carbonate, has been known since ancient times, and was mentioned in Pliny the Elder’s Natural History  under the Greek name kuanos (κυανός: “deep blue,” root of English cyan). The blue of azurite is exceptionally deep and clear, and for that reason the mineral has tended to be associated since antiquity with the deep blue color of low-humidity desert and winter skies.

Azurite is monoclinic

Hardness of 3 1/2 to 4

Azurite has been used as a pigment for centuries.

It is used in jewelry.

Azurite is unstable in open air with respect to malachite, and often is pseudomorphically replaced by malachite. This weathering process involves the replacement of some the carbon dioxide (CO2) units with water (H2O), changing the carbonate:hydroxide ratio of azurite from 1:1 to the 1:2 ratio of malachite:

2 Cu3(CO3)2(OH)2 + H2O → 3 Cu2(CO3)(OH)2 + CO2

From the above equation, the conversion of azurite into malachite is attributable to the low partial pressure of carbon dioxide in air. Azurite is also incompatible with aquatic media, such as saltwater aquariums.

 

Azurite_from_China

By Eric Hunt (Own work) [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons – Azurite from Shilu Copper Mine, Guangdong Province, China

Azurite_with_Malachite_-_National_Museum_of_Natural_History_-_Washington,_D.C.

Azurite with malachite Cu3(CO3)2(OH)2 Copper Queen mine, Bisbee, Arizona – By thisisbossi from Washington, DC, USA [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons

OLYMPUS DIGITAL CAMERA

A floater cluster of crystals radiating like a star in both directions from a central growth point. A really wonderful blue, not the near-black look that some azurites have. 4.1 x 2.0 x 1.7 cm – Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons – Locality: Touissit, Touissit District, Oujda-Angad Province, Oriental Region, Morocco (Locality at mindat.org)

Azurite-284714

An unusual habit of azurite from this mine, with matte-finish, powder-blue crystals standing in disc-like towers on contrasting matrix. Unusual. From the well-known Tucson collection of 40-year collector, Harold Urish. Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons – Locality: Morenci Mine (Morenci pit; Phelps Dodge Morenci Mine; Morenci-Metcalf), Morenci, Copper Mountain District (Clifton-Morenci District), Shannon Mts, Greenlee County, Arizona, USA (Locality at mindat.org) Size: 7.4 x 5.5 x 3.5 cm.

Azurite-Malachite-59275

A classic Arizona combo specimen, with a fine balance of green malachite and deep blue azurite side-by-side. 4.4 x 4.1 x 2.2cm – Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons – Locality: Morenci, Copper Mountain District (Clifton-Morenci District), Shannon Mts, Greenlee County, Arizona, USA (Locality at mindat.org)

 

Macon, Georgia 31210