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Download hereGENERAL DESCRIPTION
Chalcophyllite is a hydrated-, complex-, copper and aluminium arsenosulfate. This mineral forms in the oxidation zones of the copper deposits. It is associated other cupriferous minerals, like cyanotrichite, zeunerite, cornubite, caledonite, tyrolite, cuprite, chrysocolla, connelite...
Its crystals are green emerald in color, with some bluish green tints. They are opaque with a vitreous lustre and present in very fine massive agregates, with hexagonal contours, sometimes acicular. This species can be dehydrated and pseudomorphoses partially into chrysocolla.
The best crystals come from Saint-Day in the English Cornwalls (UK), Tsumeb in Namibia, the Bisbee district, Arizona in the USA also in Nevada (Majuba Hill), in Germany (Black Forests, Metallic Mounts), Sardinia, Portugal and in Chile (El Teniente, Potrerillos) but also in France.
In France, chalcophyllite is known in relatively numerous deposits such as Sainte Marie-aux-Mines (Haut-Rhin), Salsigne (Aude); Vaulry (Haute-Vienne), Val d’Ajol (Vosges), Cap Garonne (Var), Chessy (Rhône)...
The place of conservation of this type is not known.
Did you know? Chalcophyllite is so rich in water molecules and hydroxides that half of the atoms are composed of hydrogen.
HISTORY : Name derived from Greek terms "χαλκοσ" [khalkos] meaning copper and "φυλλοσ" [phyllos] meaning "leaf", in reference to its cleavage
Species described in 1841 by J.F.A. Breithaupt (1791-1873), Saxon mineralogist
Type-locality: unknown
ANCIENT NAME : Erinite
CHEMICAL FORMULA : Cu18 Al2 (AsO4)4 (SO4)3 (OH)24 36H2O
CRYSTAL SYSTEM : Hexagonal
COLOR : Emerald green to blueish green, blue
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous to subadamantine
STREAK : Light green to blue green
MORPHOLOGIE : Tabular crystals, flattened, hexagonal
HARDNESS : 2
CHEMICAL CLASS: 2,684
DENSITY : VIII - Arseniates
GROUP : Chalcophyllite-parnauite
STRUNZ CLASS BEFORE 2001 : 7/D.20-50
STRUNZ CLASS AFTER 2001 : 8.DF.15
