is a copper carbonate
hydroxide mineral, with the formula Cu2CO3 (OH)2
. This opaque, green-banded mineral crystallizes in the monoclinic crystal system
, and most often forms botryoidal
, fibrous, or stalagmitic
masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare, but occur as slender to acicular
after more tabular or blocky azurite
crystals also occur.