/floor ap"euh tuyt', flawr-, flohr-/, n.a crystalline mineral, Ca5(PO4)3F, formed from hydroxyapatite in the presence of fluoride, that has a hardening effect on bones and teeth.[1880-85; < G Fluorapatit; see FLUOR-, APATITE]
* * *▪ mineralcommon phosphate mineral, a calcium fluoride phosphate, Ca5(PO4)3F. It occurs as minute, often green, glassy crystals in many igneous rocks, and also in magnetite deposits, high-temperature hydrothermal veins, and metamorphic rocks; it also occurs as collophane in marine deposits. For detailed physical properties, see phosphate mineral (table).The fluoride ion is often replaced in the crystal structure by chloride or a hydroxide group; in nature there are complete chemical variations, called solid-solution (solid solution) series, between fluorapatite and chlorapatite and between fluorapatite and hydroxylapatite. Manganese can replace up to 10 percent of the calcium in fluorapatite derived from granite pegmatites.
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