Whitlockite

Whitlockite is named after Herbert Percy Whitlock, Curator of minerals, American Museum of Natural History, New York, USA.

Whitlockite forms transparent to translucent colourless, white, gray, yellowish or pinkish rhombohedral or tabular crystals with vitreous to resinous lustre.
General Information
Chemical Formula
Ca
 
9
(Mg,Fe
2+
 
)(PO
 
4
)
 
6
(PO
 
3
OH)
Anthony et al, Handbook of mineralogy (2001)
Photos of natural/un-cut material from mindat.org
Physical Properties of Whitlockite
Mohs Hardness5 to 0
Anthony et al, Handbook of mineralogy (2001)
Specific Gravity3.12
Anthony et al, Handbook of mineralogy (2001)
FractureUneven,Sub-Conchoidal
Anthony et al, Handbook of mineralogy (2001)
Optical Properties of Whitlockite
Optical CharacterUniaxial/-
Anthony et al, Handbook of mineralogy (2001)
Colour
Colour (General)Colorless, white, gray, yellowish; colorless in transmitted light.
Anthony et al, Handbook of mineralogy (2001)
TransparencyTransparent,Translucent
Anthony et al, Handbook of mineralogy (2001)
LustreVitreous,Resinous
Anthony et al, Handbook of mineralogy (2001) Subresinous
Crystallography of Whitlockite
Crystal SystemHexagonal
Anthony et al, Handbook of mineralogy (2001)
HabitTypically as rhombohedral crystals, rarely flat tabular, several other smaller forms, to 2 cm. May form cave pearls; as anhedral grains and microcrystalline crusts.
Anthony et al, Handbook of mineralogy (2001)
Geological Environment
Where found:An uncommon secondary mineral in complex zoned granite pegmatites; in phosphate rock deposits; may be formed in caves from leached guano; in chondrite meteorites.
Anthony et al, Handbook of mineralogy (2001)
Further Information
Mineral information:Whitlockite information at mindat.org
Significant Gem Localities
USA
 
  • New Hampshire
    • Grafton Co.
      • Groton
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