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Download hereGENERAL DESCRIPTION
Tremolite is a mineral of the amphiboles family, i.e. silicates hydrated whose silicates ions are structured in chains. Tremolite is a magnesio-calcic amphibole.
It is formed in the zones of contact metamorphism of rocks very rich in calcium and magnesium (dolomites etc). Tremolite is a very good indicator of the conditions of metamorphism being applied to sedimentary rocks.
The crystals are generally lengthened, prismatic even flattened and can measure up to 20 cm. They are transparent with translucent, have a vitreous luster and are white with gray even greenish when there are chlorite inclusions.
The principal deposits are Campolungo in Switzerland, Saint-Marcel in Italy, the district of Brumado in Brazil where crystals of 40 cm were discovered. The recent discoveries in Pakistan are interesting.
In France, tremolite is present in Auvergne in the area of Brioude-Massiac, in Brittany (Calanhel, Peumérit), Corsica (mine of Canary), Vosges (Raon-l’Etape), Pyrénées (Costabonne, Salau, Luzenac, Aure), Cau (close to Decazeville, Aveyron)...
The place of conservation of the type of this species must be that deposited with the Museum of Geneva (originally Val of Tremola but in fact of Campolungo, valley of Piumogna, Leventina, Tessin province in Switzerland). It was described in 1789.
HISTORY : Named to recall the locality where the type specimen was supposed to come from Tremola valley, Gotthard, Switzerland
Species first described in 1790 by Johann Georg Albrecht Höpfner (1759-1813), Swiss pharmacian and journalist
Type-locality : Campolungo, Tessin, Switzerland
CHEMICAL FORMULA : Ca2 (Fe2+, Mg)5 Si8O22 (OH)2
CRYSTAL SYSTEM : Monoclinic
COLOR : White, gray, pink
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous
STREAK : White
MORPHOLOGIE : Elongated crystals , prismatic, fibrous, forming aggregates
HARDNESS : 5,0-6,0
CHEMICAL CLASS: 2,964
DENSITY : VIII - Silicates
GROUP : Clinoamphibole (Ca)
STRUNZ CLASS BEFORE 2001 : 8/F.10-10
STRUNZ CLASS AFTER 2001 : 9.DE.10
