Needle crystals of pyromorphite, Tao Ping mine, China. The field of view of the photograph is 8 mm. — Photo: Masha Milshina · CC BY 4.0
Pyromorphite
Lead chlorophosphate — a secondary lead ore forming hollow 'campionite' hexagonal prisms in green and yellow.
Intro adapted from Wikipedia (CC BY-SA).
Pyromorphite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Pb₅(PO₄)₃Cl.
It crystallizes in the hexagonal crystal system (space group P6_3/m). It is a member of the Apatite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 7.04; White streak; Resinous to subadamantine luster; optically uniaxial.
IMA symbol Pym, grandfathered status — known before the IMA’s founding, named in 1813.
Found as a secondary mineral in the oxidized zone of lead deposits; rarely a volcanic sublimate.
It is found associated with Cerussite, anglesite, smithsonite, willemite, galena.
Its name comes from the Greek for fire and form, as melted globules will recrystallize.