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Download hereGENERAL DESCRIPTION
Almandine is a iron and aluminium silicate, that belongs to the garnets group of minerals. Almandine is formed in metamorphic rocks (schists, eclogites...) and in some metamorphic pegmatites.
It is associated to aluminosilicates (andalusite, sillimanite, kyanite), with cordiétite, staurolite, among others. The crystals form regular dodecahedra, with a red-black to pink-purplish color. It is not rare to locally find almandite crystals of big size (higher than 30 cms).
If almandine is known in almost all the countries, some deposits are remarkable for the quality of their specimens like in Pedra Lavrada in Brazil (crystals of 3 cm in quartz nodules), the N’Chwaning mine in Republic of South Africa, in Emerald Creek in Idah (USA, with crystals of 5 cm showing an asterism), the garnet mine of Barton in the state of New York (crystals of one meter!!) and in Wrangell (Alaska, USA) and even in places a little more unexpected like in the Antarctic... Gemmeous almandines are present in the alluvials of Sri Lanka and Jaïpur in India.
In France, garnets almandines are widespread in all crystalline massifs. Among hundreds of deposits, one can quote the mines of Batère in the Pyrénées Orientales, Pont-de-Salars in Aveyron or Rive de Gier in the Loire... We can also point out the beach of Les Chats in Ile de Groix (Brittany), which sand is mostly made of red garnets. Overseas, almandine is also known in Martinique (Islet Gris) and in French Guyana (river Haute Sparaouine).
The place of conservation of the type of this species is not known.
Did you know? Louis XIV made install a factory of stone size in the port of Syriam (Burma). Almandite was then called "Syrian" or "garnet-red garnet of Syria". Apart from the jewellery and jewellery, one used almandite in ornamentation enormously.
The national Natural history museum of Natural History has in its collections a salt box worked in a garnet almandite. This salt box is exposed in the room of the treasure of the Gallery of Mineralogy.
HISTORY : Name derives from the ancient merchant city Alabanda in Minor Asia, this city is considered as one of the biggest centers of stone size in Antiquity
Species described by Caius Plinius Secundus better known as Pliny the Elder (AD 23 – August 24, AD 79), an ancient author, naturalist or natural philosopher and naval and military commander
Type-locality: Alabanda, province de Aydin, Turquie
ANCIENT NAME : Grenat syrien, grenat de Syrie
CHEMICAL FORMULA : (Fe2+)3 Al2 (SiO4)3
CRYSTAL SYSTEM : Cubic
COLOR : Deep red to red-violet, black
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous to resineous
STREAK : White
MORPHOLOGIE : Dodecahedra crystals well formed
HARDNESS : 7,0-7,5
CHEMICAL CLASS: 4,313
DENSITY : VIII - Silicates
GROUP : Grenat
STRUNZ CLASS BEFORE 2001 : 8/A.08-20
STRUNZ CLASS AFTER 2001 : 9.AD.25
