Garnets

Garnets

An isomorphous group of minerals with general formula 8[A3B2(SiO4)3]. Cubic system. Mainly dodecahedral or tetragonal trioctahedral crystals. Vitreous to resinous luster. No cleavage. Conchoidal to uneven fracture. Brittle to tough. Garnets are divided in 2 groups; ugrandite an isomorphous intermediate group of uvarovite-grossularite-andradite and pyralspite an isomorphous intermediate group of pyrope-almandine-spessartine. Some garnets show anomalous double refraction between crossed polarizing microscopes due to stress.

See Alexandrite Tsarstone collectors guide, Definition of Garnets, http://m.alexandrite.net/viewpage.html?id=GG-092-00001 (An isomorphous group of minerals with general formula 8[A3B2(SiO4)3]. Cubic system. Mainly dodecahedral or tetragonal trioctahedral crystals. Vitreous to resinous luster. No cleavage. Conchoidal to uneven fracture. Brittle to tough. Garnets are divided in 2 groups; ugrandite an isomorphous intermediate group of uvarovite-grossularite-andradite and pyralspite an isomorphous intermediate group of pyrope-almandine-spessartine. Some garnets show anomalous double refraction between crossed polarizing microscopes due to stress. ) (as of Apr. 03, 2026, 14:12 GMT).