Class: Silicates
Group: Vesuvianite
Original description: ‘Vesuvian’ Klaproth, M. H., 1795. Vesuvian, hellbrauner — Beiträge zur Chemischen Kenntniss der Mineralkörper 1: 34—35 [
view in ‘Library’].
Type locality: Monte Somma, Somma-Vesuvius Complex, Naples Province, Campania, Italy.
Type material: Technische Universität Bergakademie, Freiberg, Germany, 23278 (
Anthony et al., 2001—2005).
Etymology: re-named ‘vesuvian’ after its type locality, Mount Vesuvius, Campania, Italy.
Distribution: Canada: Asbestos and Mont Saint-Hilaire, Quebec; Italy: at Monte Somma and Vesuvius, Campania; Mexico: Chihuahua; Norway: Arendal; Russia: near Zlatoust, Urals; Switzerland: near Zermatt, Valais; USA: California (
Anthony et al., 2001—2005).
Chemistry
Ca10Mg2Al4(SiO4)5(Si2O7)2(OH)4
Essential elements: hydrogen (H), oxygen (O), magnesium (Mg), aluminium (Al), silicon (Si), calcium (Ca).
Crystal data
Crystallography: tetragonal — dipyramidal.
Crystal habit: commonly as short pyramidal to long prismatic crystals, to 15 cm, morphologically complex, with up to 30 forms reported on one crystal; columnar, granular, massive (
Anthony et al., 2001—2005).
Optical properties
Colour: yellow, green, brown; colourless to white, blue, violet, bluish green, pink, red, black, commonly zoned; in transmitted light, colourless to light yellow, green, brown (
Anthony et al., 2001—2005).
Diaphaneity: transparent to translucent (
Anthony et al., 2001—2005).
Lustre: vitreous to resinous (
Arem, 1987: 115).
Refractive index: 1.7—1.725 — anisotropic [uniaxial (+/-)] (
Lazzarelli, 2012).
Birefringence: 0.002—0.012.
Dispersion: 0.019—0.025 (
Arem, 1987: 115).
Pleochroism: weak; O = colourless to yellowish; E = yellowish, greenish, brownish (
Anthony et al., 2001—2005).
Material from ‘Repository’