Azurite
Azurite is a bright blue secondary copper mineral - that means it is formed by alteration
of other copper minerals. It is formed by aqueous solutions of copper acting on
limestone or by carbonated waters acting on other copper-minerals. It is typically found
as crystals or coatings on rock in the upper part - the so-called oxidation zone - of
copper deposits, but it may also form micro-crystals or blue smear on rocks on mine
dumps. It is often associated by other secondary copper minerals, particularly Malachite
The name 'Azurite' is derived from the Persian lazhward, meaning blue colour,
and Azurite has indeed been used as blue pigment for paintings through history. This has
caused occasional problems on antique paintings, when the Azurite alters to green
Malachite. Alteration of Azurite to Malachite is quite abundant in nature, and many
localities producing Azurite crystals also carry very attractive Malachite pseudomorph
after Azurite. Very attractive specimens of Tennantite pseudomorph after Azurite have
been in Tsumeb (Oshikoto Region, Namibia), and they are often far less expensive than
specimens of unaltered Azurite crystals of the same size.
Azurite is quite abundant, and known from most copper deposits, whether worked as
mines or not. By far the most spectacular crystals come from Tsumeb (Oshikoto Region,
Namibia), but wonderful rosettes come from La Sal (Utah, USA), Chessy (near Lyon,
France) and Shilu (Guangdong Province, China). Superb cutting material and aesthetic
specimens are known from Bisbee and Morenci (Arizona, USA).
Our records indicate that Azurite from a range of deposits occurs on specimens that also
carry one or more of the following minerals: Achantite, Anglesite, Antlerite, Aragonite,
Arsentsumebite, Atacamite, Aurichalcite, Barite, Bayldonite, Beudantite, Bismite,
Brochantite, Calcite, Cerussite, Chalcocite, Chalcophyllite, Chalcopyrite, Chalcostibite,
Chlorargyrite, Chrysocolla, Conichalcite, Copper, Cornubite, Cornwallite, Cuprite,
Dolomite, Duftite, Dundasite, Erythrite, Fluorite, Gibbsite, Goethite, Graphite,
Hematite, Hessite, Lavendulane, Malachite, Muscovite, Olivenite, Otavite, Partzite,
Phlogopite, Pyrite, Pyrolusite, Pyromorphite, Quartz, Smithsonite, Sphalerite,
Tennantite, Tenorite, Tetrahedrite, Theisite, Tsumebite, Tyrolite, and Villamaninite.
Specimen Handling
Azurite is water soluble! No, it does not say so in your mineralogy book, and the
process is slow, but it is nevertheless soluble. If you fill a bucket with Azurite and tap
water, the water will turn dark blue in a matter of hours. A specimen is not necessarily
harmed by a quick rinse in water with detergent, but it is far better to just blow off the
dust. Azurite is not suitable for aquaria, potted plants, garden rock, any setting with live
organisms, or where it is exposed to high humidity or water.
Azurite is for all practical purposes stable in a normal household environment. It is not
harmed by light, changes in temperature in the normal comfort range, or known to
decompose, apart from the long-term alteration into Malachite, described above,
probably caused to humidity and possibly acidity in old paintings. Azurite can be brittle
and should be handled with care like any other mineral specimen.
Bibliography
Bancroft, Peter. 1984. Gem & Crystal Treasures.
Blackburn, William H. & William H. Dennen. 1997. Encyclopedia of mineral
names. Canadian Mineralogist, special publication 1.
Gaines, Richard W., H. Catherine W. Skinner, Eugene E. Foord, Brian Mason,
Abraham Rosenzweig & Vandall T. King. 1997. Dana's new mineralogy: the
system of mineralogy of James Dwight Dana and Edward Salisbury Dana, 8th
ed.
Gebhard, Georg. 1991. Tsumeb, eine deutsch-afrikanische Geschichte.
Gebhard, Georg. 1999. Tsumeb, a unique mineral locality.
Hintze, Carl (ed.) 1897-1939. Handbuch der Mineralogie.
Noe-Nygaard, Arne. 1966. Mineralogi, 3rd ed.
Palache, Charles, Harry Berman & Clifford Frondel. 1951. The system of
mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University
1837-1892, 7th ed. Vol. 2.
Ramdohr, Paul & Hugo Strunz. 1980. Klockmann's Lehrbuch der Mineralogie,
16th ed.
Roberts, Willard Lincoln, Thomas J. Campbell & George Robert Rapp jr. 1990.
Encyclopedia of Minerals 2nd ed.
Sinkankas, John. 1964. Mineralogy.
This page is authored by Claus Hedegaard.
