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Class: Silicates
Group: Garnet

The most common garnet; typically in mica schists and gneisses, from regionally metamorphosed argillaceous sediments; in granites and eclogites; in sedimentary rocks (Anthony et al., 2001—2005).
Almandine — specimen 0643
Almandine — specimen 0643, photo © NMNHS

Original description: unknown.

Type locality: Alabanda, Aydın Province, Turkey.

Type material: unknown.

Etymology: named in 1546 by Georgius Agricola for Alabanda in Turkey.

Distribution: widespread; some localities for fine crystals include: Australia: Northern Territory, Harts Range; Austria: Tirol, Zillertal; Brazil: Bahia, Pernambuco; Russia: Akhmatovsk deposit, near Zlatoust, Urals; Sweden: Falun; USA: New York, Warren Co., North Creek, Barton mine (Anthony et al., 2001—2005).



Essential elements: oxygen (O), aluminium (Al), silicon (Si), iron (Fe).

Crystal data

Crystallography: isometric — hexoctahedral. Crystal habit: typically well-formed dodecahedra or trapezohedra, to 1 m; also in rounded grains and massive (Anthony et al., 2001—2005).

Physical properties

Cleavage: parting on {110} (Anthony et al., 2001—2005). Fracture: subconchoidal (Anthony et al., 2001—2005). Tenacity: brittle (Anthony et al., 2001—2005). Hardness: 7—7.5 (Lazzarelli, 2012). Density: 3.95—4.3 g/cm3 (Arem, 1987: 105). Luminescence: none (Arem, 1987: 105).

Optical properties

Colour: deep red, brownish red, red-violet, black; may be sectored (Anthony et al., 2001—2005). Diaphaneity: transparent to translucent (Anthony et al., 2001—2005). Lustre: vitreous to resinous (Anthony et al., 2001—2005). Refractive index: 1.77—1.82 — isotropic (Lazzarelli, 2012). Dispersion: 0.027. Pleochroism: none.

Material from ‘Repository’

5 specimens: 0649 — 0.98 ct, Tanzania; 0632 — 0.29 ct, Madagascar; 0236 — 1.53 ct, Madagascar; 0430 — 0.73 ct, Madagascar; 0643 — 0.66 ct, Madagascar.

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