Smithite

Smithite
Red smithite with imhofite
General
Categorysulfosalt mineral
FormulaAgAsS2
IMA symbolSth
Strunz classification2.GC.30
Crystal systemMonoclinic
Identification
Formula mass246.92 g/mol
ColorPale red (changes to orange on exposure to light)
Crystal habithexagonal pyramid
CleavagePerfect, parallel to (100)
Mohs scale hardness1.5 – 2
LusterAdamantine
Streakvermilion
Specific gravity4.88
References

Smithite is a sulfosalt mineral with the chemical formula AgAsS2. It was first described by mineralogist R H Solly in 1905, in samples from the Lengenbach quarry near Binn, Switzerland, and was named for Herbert Smith, who was an assistant in the department of mineralogy of the British Museum (Natural History). Smithite is a dimorph of trechmannite.