CHEMISTRY Pb5(PO4)3Cl
CRYSTALLOGRAPHY Hexagonal
CRYSTAL GROWTH AND HABITS Pyromorphite is prismatic, sometimes with hopper or skeletal growth. It also forms in radiating or branching groups. Pyromorphite is also found as globular, botryoidal and reniform masses.
COLOR AND OTHER OPTICAL PROPERTIES Pyromorphite commonly is found in various shades of green but also yellow to orange and brown. It is transparent to translucent.
HARDNESS 3.5 - 4
SPECIFIC GRAVITY 7.0- 7.1
LUSTER Vitreous, resinous to sub adamantine
STREAK White
BREAKABILITY Pyromorphite has an uneven to subconchoidal fracture and is brittle.
OCCURRENCE Pyromorphite is a secondary mineral found in the oxidized zone of lead deposits.
ASSOCIATED MINERALS Cerussite, anglesite, smithsonite, galena
NAME From the Greek "pyro" for fire and "morph" for form. This refers to its property of taking on a crystalline form after it has been melted in laboratory studies.