Serpierite

Sources differ widely about the hardness of serpierite, giving values varying between 2 and 4. They all agree, however, that the specific gravity is 3.07, a very little less than the calculated value. Cleavage is perfect perpendicular to the c direction, which is the direction in which the crystals are flattened. The mineral is brittle and breaks with a splintery fracture. It is soluble in acids and it is not radioactive.

Serpierite is a sky-blue coloured mineral, with a white or almost white streak and a vitreous lustre, pearly on cleavages. It is transparent, and appears greenish-blue in transmitted light. No large crystals have been found. It occurs as tufts and crusted aggregates of lath-like or bladed crystals typically less than 1 mm long. These crystals are elongated along the crystallographic direction a, and flattened perpendicular to the c direction.

The type locality is the Serpieri Mine, Kamariza, Lavrion District, Greece, and type material is conserved at the National Museum of Natural History, Paris, France, reference 73.38, 78.226. Serpierite is a secondary mineral found in altered smelter slags and oxidised sulfide veins. At the type locality it is associated with smithsonite and it has also been found associated with devilline, posnjakite, ktenasite, linarite, langite, brochantite, wroewolfeite, namuwite, schulenbergite, hydrozincite, malachite and gypsum.