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Download hereGENERAL DESCRIPTION
Gormanite is a hydrated iron and aluminum phosphate, which is formed in the hydrothermal veins (low temperature) within rocks enriched in phosphate and iron.
The crystals are prismatic and are lengthened: they can form radial clusters. They are blue-green in colour and semi-transparent.
The occurences of gormanite are very few. One can quote Rapid Creek in Canada and Lavra Gormanita in Brazil. Only one site provided crystals of greater dimensions: Bisbee (Arizona, USA).
In France, gormanite is present in the gold mine of Salsigne (Aude).
The sample-types of this species are kept at the Royal Ontario Museum of Toronto and at the National Museum of Natural History in Washington. It was described in 1981 on a sample from Rapid Creek, mining district of Dawson, Yukon Territory in Canada.
HISTORY : Species dedicated to Donald Herbert Gorman (1922- ), professeur of mineralogy, University of Toronto, Canada
Species first described in 1981 by B. Darko Sturman et al.
Type-locality : Big Fish River and Blow River, Yukon, Canada
CHEMICAL FORMULA : Fe3 Al4(PO4)4(OH)6 2H2O
CRYSTAL SYSTEM : Triclinic
COLOR : Blue-green
DIAPHANIETY : Semi-transparent
LUSTER : Vitreous
STREAK : Light green
MORPHOLOGIE : Elongated crystals
HARDNESS : 4,0-5,0
CHEMICAL CLASS: 3,10-3,12
DENSITY : VII - Phosphates, arsenates and vanadates
GROUP : Souzalite
STRUNZ CLASS BEFORE 2001 : 7/D.11-100
STRUNZ CLASS AFTER 2001 : 8.DC.45
