What is Whitlockite?
Whitlockite is a calcium phosphate of the merrillite family, found in phosphate-rich rocks and meteorites and important in both mineralogy and biomineral research.
Mineralogy and structure
Reference formula: Ca9(Mg,Fe)(PO4)6PO3OH. Whitlockite is trigonal and natural material commonly contains magnesium and iron. COD 1534465 is a labelled Fe-bearing representative model for the whitlockite structure. Whitlockite is classified with phosphates and has trigonal crystal symmetry. Typical hardness is 5–5.5 on the Mohs scale and specific gravity is approximately 3.1–3.2.
Colour, lustre and habit
Typical colours include colourless, white, grey, yellowish, brown. The usual granular, massive, crusty habit and vitreous, pearly, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Whitlockite forms in or is associated with granitic pegmatites, phosphate-rich metamorphic rocks, meteorites and biological or laboratory phosphate systems. Important documented localities include the United States, Brazil, Sweden, Germany, meteorites and lunar samples.
A calcium phosphate linking rocks and meteorites
Whitlockite is a valuable bridge mineral: the same structural family appears in terrestrial phosphate environments and extraterrestrial material, giving a small specimen an unusually broad story.
Collecting and care
Protect from acids and abrasion; document whether the sample is geological, meteoritic or synthetic because origin changes interpretation.
