Apatite is a widely distributed accessory constituent in all classes of rock. Found in crystals and masses, crystallised apatite has been extensively used for fertiliser. Transparent varieties of a fine colour are sometimes used for gems - but it's too soft for extensive use. Apatite has the formulae Ca5(F,Cl,OH)(PO4)3 and a relative hardness of and crystallizes in a regular six-sided prism, usually terminated by a truncated six-sided pyramid. It passes through various shades of colour, from white to yellow, green, blue, and occasionally red, scratches fluorspar but is scratched by felspar, and has a specific gravity of about 3.5. It is a compound of phosphate of lime with fluoride and chloride of calcium. Research Apatite
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Rocks & Minerals
Research Apatite
