pseudomalachite

Pseudomalachite is a rare copper phosphate mineral with the chemical formula Cu5(PO4)2(OH)2. It is often found in association with malachite and azurite, other copper carbonate minerals. Pseudomalachite typically forms in arid or semi-arid environments where copper-rich rocks are exposed to weathering. Its name derives from its resemblance to malachite, another copper mineral, but pseudomalachite is a phosphate rather than a carbonate.

This mineral commonly occurs as fibrous or botryoidal aggregates, and sometimes as granular masses. The color of pseudomalachite is typically a bright to dark green, similar to malachite, though it can also exhibit blue-green hues. It is a relatively soft mineral, with a Mohs hardness of 4 to 4.5, and has a specific gravity of approximately 3.4. Pseudomalachite is not known for any significant economic uses, but it is collected by mineral enthusiasts for its attractive appearance and its interesting mineralogical relationships. It is found in various locations worldwide, often in copper mining districts, including the United States, Chile, and the Democratic Republic of Congo.