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Malachite, Azurite, Siderite, 









Malachite: Hydrous Copper Carbonate 
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Malachite (Cu2CO3(OH)2)



Malachite is generally a bright emerald green colour with individual crystals illustrating an
 adamantine lustre.
Acicular (needle shaped) crystals are common but malachite usually forms
 as either a film on other copper minerals or as botryoidal/reniform masses with a banded structure. Hardness is between 3.5-4 with a perfect cleavge. Malachite forms in the oxidation zones of 
copper deposits as a result of the reaction of sulphides with carbonates. It is associated with
 azurite, cuprite and native copper. World class deposits in Russia (Urals), Zaire (Katanga),
 Zambia, Arizona (Bisbee) and Germany (Betzdorf).



Uses: Mainly as a decorative stone and an ore of copper.











Azurite: Hydrous Copper Carbonate 
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Azurite (Cu3(CO3)2(OH)2)



Azurite is usually an azure-blue in colour but can be darker in crystals. Lustre is generally vitreous
 to adamantine with a hardness of 3.5-4. Crystals are either elongate or tabular-prismatic in habit
 but can also form complex radiating aggregates. Azurite is a common secondary mineral in the
 oxidised zone of copper deposits along with malchite. It forms at lower temperatures than
 malachite and can often be replaced by it through hydration. Azurite is also associated with
 carbonate rocks.  World class deposits are rare as it is less widely distributed than malachite.
 Some good crystals are found in Arizona (Bisbee), France (Lyon), Greece (Laurium) and Namibia (Tsumeb).



Uses: Mainly as a decorative stone and an ore of copper.











Siderite: Iron Carbonate 
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Siderite (FeCO3)



Siderite's colour varies from brown, yellowish-brown, grey-brown to white, all with a vitreous/
pearly lustre. Crystals are rhombohedral with curved, striated faces. Botryoidal, compact and 
oolitic masses are common. Hardness is between 3.5-4.5 with a perfect rhombohedral cleavage. Siderite is common in low to medium temperature hydrothermal veins associated with fluorite,
 barite, galena and sphalerite. Even more common in sedimentary deposits as concretions in clays
 and shales. World class deposits found in Austria (Styria), England (Cornwall), Brazil, Canada and Greenland.



Uses: An important ore of iron. Also some use to collectors and scientists.









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