Azurmalachite

Azurmalachite forms at shallow depths in the oxidizing zone above copper deposits, where slightly acidic copper-bearing waters seep down and precipitate copper carbonates in fractures, cavities and pores, often in limestone or marble host rock. Bands record conditions that alternated between those favouring azurite and those favouring malachite; azurite is also often replaced by malachite. It is a by-product of copper mining; much of the material sold comes from the southwestern United States (for example the Morenci Mine, Arizona), France and Namibia.

Azurmalachite is identified by its combined blue and green colours, high specific gravity (3.6 to 4.0), low hardness (3.5 to 4), perfect cleavage and clear fizzing in dilute hydrochloric acid. Because it is porous, some material is impregnated with resin to improve durability. Thin slabs are also glued to a durable backing such as chalcedony or jade to make doublets. "Reconstructed" azurmalachite, a compressed and plastic-impregnated mixture of crushed azurite and malachite, has been sold since at least 1989, sometimes as "synthetic", and some has been found to contain artificial copper veins.

Azurmalachite scratches easily, has perfect cleavage and lacks toughness, so it suits earrings, pins and pendants in protective settings rather than rings or bracelets. Store pieces in separate bags or compartments to avoid abrasion.