Class: Phosphates, arsenates, vanadates
Group: Apatite
Original description: ‘Apatit’ Rammelsberg, C. F., 1860. Apatit — Handbuch der Mineralchemie, Wilhelm Engelmann, Leipzig: 351—355 [
view in ‘Library’].
Type locality: Greifenstein, Ehrenfriedersdorf, Erzgebirge, Saxony, Germany.
Type material: unknown.
Etymology: renamed from the original ‘apatite’ to emphasise the chemical composition. Apatite is from the Greek
απατείν (apatein), ‘to deceive’, as it was often confused with other minerals.
Distribution: many localities: Afghanistan: Kunar Province; Brazil: Minas Gerais, Nova Lima; Canada: large crystals from southeastern Ontario; Germany: Saxony, at Ehrenfriedersdorf; Mexico: Durango, Cerro de Mercado; Pakistan: Gilgit-Baltistan; Russia; South Africa (
Anthony et al., 2001—2005). Facetable material is known from Madagascar.
Chemistry
Ca5(PO4)3F
Essential elements: oxygen (O), fluorine (F), phosphorus (P), calcium (Ca).
Crystal data
Crystallography: hexagonal — dipyramidal.
Crystal habit: as prismatic hexagonal crystals, elongated on [0001], to 2 m; as complex tabular to discoidal crystals flattened on {0001}, typically with many forms; granular, globular to reniform, nodular, massive.
Twinning: rare as contact twins on {1121} or {1013} (
Anthony et al., 2001—2005).
Optical properties
Colour: sea-green, violet, purple, blue, pink, yellow, brown, white, colourless; may be zoned; colourless or faintly tinted in thin section (
Anthony et al., 2001—2005).
Diaphaneity: transparent to translucent (
Anthony et al., 2001—2005).
Lustre: vitreous to subresinous (
Anthony et al., 2001—2005).
Refractive index: 1.631—1.646 — anisotropic [uniaxial (-)] (
Anthony et al., 2001—2005).
Dispersion: no data.
Pleochroism: weak to strong if coloured (
Anthony et al., 2001—2005).
Material from ‘Repository’