Azurite

Azurite from Mineral Hill, Condobolin, New South Wales, Australia, measuring 74 × 52 × 28 mm and weighing 128 grams. A good-sized copper carbonate specimen from a long-worked central New South Wales mining field.

Azurite is copper carbonate hydroxide, Cu3(CO3)2(OH)2, and its name comes from the old Persian word for blue, the same root as lapis lazuli. It contains slightly less water and more carbonate than Malachite, and over time, in contact with moist air and groundwater, it tends to alter to Malachite, which is why so many specimens show the two together or Malachite in Azurite's crystal shape. It has been ground for a blue pigment since antiquity.

Mineral Hill lies north of Condobolin in the Lachlan Fold Belt, a polymetallic copper-gold-lead-zinc-silver deposit that has been worked on and off since the early twentieth century. Like most copper deposits, its upper levels weathered to produce the secondary copper carbonates. Central New South Wales Azurite such as this David Vince Collection piece makes a good complement to the better-known South Australian and Queensland material.