Pyromorphite is a lead mineral characteristic of the oxidation zones of lead and lead-zinc ores. The usual color is green. Other colors are rare. It often forms pseudomorphs after other lead minerals. It is practically never found in large quantities. Of interest to collectors.
You can see pyromorphite stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Phosphate mineral Apatite group |
Formula (repeating unit) |
Pb5(PO4)3Cl |
IMA symbol | Pym |
Strunz classification | 8.BN.05 |
Crystal system | Hexagonal |
Crystal class | Dipyramidal (6/m) (same H-M symbol) |
Space group | P63/m |
Identification | |
Color | Dark green to grass-green or green, yellow, yellow-orange, reddish orange, yellow-brown, greenish-yellow or yellowish-green, shades of brown, tan, grayish, white and may be colorless; colourless or faintly tinted in transmitted light. |
Crystal habit | Prismatic to acicular crystals, globular to reniform |
Twinning | Rarely on {1122} |
Cleavage | Imperfect- [1011] |
Fracture | Uneven to sub-conchoidal |
Tenacity | Brittle |
Mohs scale hardness | 3.5-4 |
Luster | Resinous to subadamantine |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 7.04 measured, 7.14 calculated |
Optical properties | Uniaxial (-) May be anomalously biaxial - |
Refractive index | nω = 2.058 nε = 2.048 |
Birefringence | δ = 0.010 |
Pleochroism | Weak |
Ultraviolet fluorescence | May fluoresce yellow to orange under LW and SW UV |
Other characteristics | Piezoelectric if biaxia |