Original description: Dana, J. D., Brush, G. J., 1868. Lime-Irongarnet; Andradite — A System of Mineralogy, John Wiley and Sons, New York: 268—270 [
view in ‘Library’].
Type locality: Drammen, Buskerud, Norway.
Type material: unknown.
Etymology: in honour of José Bonifácio de Andrada e Silva, Brazilian mineralogist.
Distribution: Mexico: Chihuahua; Norway: Arendal; Russia: from the Bobrovka River, Nizhny Tagil, Urals; South Africa: Cape Province, near Kuruman; Switzerland: Valais, Zermatt; USA: Alaska, on Prince of Wales Island; Arkansas, Hot Spring Co., Magnet Cove; California, San Benito Co. (
Anthony et al., 2001—2005). Good facetable material from Namibia.
Crystal data
Crystallography: isometric — hexoctahedral.
Crystal habit: commonly well-crystallised dodecahedra, trapezohedra, or combinations, to 5 cm; also granular to massive (
Anthony et al., 2001—2005).
Optical properties
Colour: yellow, greenish yellow to emerald-green, dark green; brown, brownish red, brownish yellow; greyish black, black; may be sectored (
Anthony et al., 2001—2005).
Diaphaneity: transparent to translucent (
Anthony et al., 2001—2005).
Lustre: adamantine to resinous, dull (
Anthony et al., 2001—2005).
Refractive index: 1.88—1.94 — isotropic (
Lazzarelli, 2012).
Dispersion: 0.057 (
Arem, 1987: 104).
Pleochroism: none.