AZURITE [ Carbonates ]

Cu3(CO3)2(OH)2, copper Carbonate Hydroxide : ornamental stone, pigment, minor ore of copper, and jewellery

Azurite is a very popular mineral because of its unparalleled colour, a deep blue called “azure”, hence its name. Azure is derived from the arabic word for blue. The colour is due to the presence of copper (a strong colouring agent), and the way the copper chemically combines with the carbonate groups (CO3) and hydroxyls (OH). Azurite has been used as a dye for paints and fabrics for eons. Unfortunately, at times its colour is too deep and larger crystals can appear black. Small crystals and crusts show the lighter azure colour well. Azurite is often associated with its colourful close cousin, malachite.

Azurite is used in jewellery and for dyes as mentioned above. It is also an unimportant ore of copper, although its significance has been more impressive in the past. It is still considered a minor ore of copper; mostly because it is found associated with other more valuable copper ores. Fine crystal clusters, nodular specimens, and interesting and beautiful combinations with malachite are important pieces in anyone’s mineral collection. The magnificent colour of azurite is worth mentioning again as it truly is a one-of-a-kind in the mineral world. Azurite is one of those classic minerals

Physical Characteristics

Colour: azure, deep blue or pale blue if found in small crystals or crusts

Luster: vitreous to dull depending on habit

Transparency: Transparent if in thin crystals, otherwise translucent to opaque

Crystal System: monoclinic; 2/m

Crystal Habits: crystals are irregular blades with wedge shaped terminations. Also, aggregate crusts and radiating, botryoidal, nodular and earthy masses

Cleavage: good in one direction and fair in another

Fracture: conchoidal and brittle

Hardness: 3.5 – 4

Specific Gravity: 3.7+ (heavier than average)

Streak: blue

Associated Minerals: numerous and include malachite, limonite, calcite, cerussite, quartz, chalcopyrite, native copper, cuprite, chrysocolla, aurichalcite, shattuckite, liroconite, connellite and other oxidized copper minerals

Major Occurrences: special localities produce some outstanding specimens especially from Lasal, Utah; Bisbee, Arizona and New Mexico, USA; Mexico; Tsumeb, Nambia; Shaba, Congo; Toussit, Morocco; Australia and in many locations in Europe

Best Indicators: colour, softness, crystal habits and associations

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