Picture of the day

Pyromorphite is a mineral species composed of lead chlorophosphate: Pb₅(PO₄)₃Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. First distinguished chemically by Martin Heinrich Klaproth in 1784, it was named pyromorphite by Johann Friedrich Ludwig Hausmann in 1813. It is usually green, yellow or brown in color, with a resinous lustre. Crystals are common and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Other forms include crystals with a barrel-like curvature and globular or reniform masses. Pyromorphite is part of the apatite group of minerals and bears a close resemblance physically and chemically with two other minerals, mimetite and vanadinite. This focus-stacked photograph, merged from 26 separate images, shows a sample of pyromorphite extracted from the Resuperferolitica Mine in Santa Eufemia, in the Spanish province of Córdoba. The sample measures 3.5 cm × 3.0 cm × 1.5 cm (1.38 in × 1.18 in × 0.59 in).Photograph credit: David Ifar