Name/Title
PyromorphiteEntry/Object ID
2004.1.21Description
Assemblage Zone: pegmatite dikes
Chemical Composition: Pb5(PO4)3Cl
Crystal System: Hexagonal System
Description: Common Name: Pyromorphite
Group Name:Apatite
Chemistry: Pb5(PO4)3Cl , Lead Chlorophosphate
Location: Yangshue County, China
Description: Small light green crystals with white and tan background.
PHYSICAL CHARACTERISTICS:
Color is typically green, but can also be yellow, orange and brown.
Luster is resinous to adamantine.
Transparency: Crystals are rarely transparent, but usually translucent.
Crystal System is hexagonal; 6/m
Crystal Habits include the typical barrel shaped hexagonal prism with the hexagonal pyramid and/or a pinacoid as a termination. A classic specimen of Pyromorphite shows its arborescent habit as described above. Also granular, reniform, encrusting and massive.
Cleavage is absent.
Fracture is uneven.
Hardness is 3.5 - 4.
Specific Gravity is approximately 7.0+ (very heavy for translucent minerals)
Streak is off white.
Associated Minerals are cerussite, limonite, galena and secondary lead deposit minerals.
Other Characteristics: Index of refraction is 2.05 (typically high for lead minerals) and crystal terminations can be hollowed out or pitted.
Best Field Indicators are crystal habit, color, lack of transparency and density.
Fracture: uneven
Hardness: 3 Calcite
Luster: Resinous
Occurrence: 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. 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.
Notable Occurrences include Idaho and Pennsylvania, USA; Mapimi, Mexico; Germany; England and Australia.
Specific Gravity: 27.0
Streak: off Whie
Variety: Pyromorphite shares the same structure with apatite and therefore crystals of the two will have similar shapes. Pyromorphite also forms a chemical series with two other minerals; Mimetite (Pb5(AsO4)3Cl) and Vanadinite (Pb5(VO4)3Cl). This series is a little different than most chemical series which involve substitution of cations such as calcium for magnesium. Instead, this series substitutes its basic chemical units the anion groups; phosphate (PO4), arsenate (AsO4) and vanadate (VO4). Green Mimetite or yellow Pyromorphite can make identification between the two difficult, but usually pyromorphite is green and mimetite is yellow. Vanadinite is usually red. Pyromorphite's main characteristic is its unique crystal habit of stacked barrel shaped crystals that branch out in a way that is reminescent of some branching cactus varieties.Collection
Suomynona Mineral Collection, Suomynona CollectionDimensions
Width
6 inDepth
2-3/4 inLength
6 inWeight
2.14 ozDimension Notes
Dimension taken at widest pointsLocation
Location
Display Case
FS-9Room
Frieda Smith HallBuilding
Crater Rock MuseumDate
August 4, 2023