Pyromorphite

Formula: Pb5(PO4)3Cl

Colour: Green to dark green, yellow, greenish-yellow or yellowish-green, orangish-yellow, shades of brown, white and colourless; colourless or faintly tinted in transmitted light.

Lustre: Sub-Vitreous, Resinous, Waxy, Greasy

Hardness: 3½ – 4

Specific Gravity: 7.04

Crystal System: Hexagonal. Crystals may be simple hexagonal prisms or rounded and barrel-shaped, spindle-shaped, or cavernous.

Member of: Apatite Group > Apatite Supergroup, Mimetite-pyromorphite series. The phosphate analogue of mimetite and vanadinite.

Name: Named pyromorphite in 1813 by Johann Friedrich Ludwig Hausmann from the Greek for “fire” and “form”, because, after being melted into a globule, a sample will begin to take on a crystalline shape during cooling.

Type Locality: Zschopau, Erzgebirgskreis, Saxony, Germany

Isostructural with: Mimetite, Vanadinite

A secondary lead mineral found in the oxidized zones of lead deposits. Typically found as green, yellowish, brownish, greyish or white barrel-shaped hexagonal prisms, in clusters or as druses on matrix. The individual crystals are often modified or etched, giving a hopper-like appearance. This lead chloride phosphate forms a complete series with mimetite (lead chloride arsenate), and many specimens are intermediates between the two end-members. Also forms a series with hydroxylpyromorphite and fluorpyromorphite. There is a complete series between mimetite, pyromorphite and vanadinite.