Gratonite

Not to be confused with Graftonite.
Gratonite

Gratonite, Excelsior Mine, Cerro de Pasco, Peru, the type locality. 1.7 x 1.6 x 1.5 cm.
General
Category Sulfosalt minerals
Formula
(repeating unit)
Pb9As4S15
Strunz classification 02.JB.55

Gratonite is a lead-arsenic sulfosalt mineral, with the chemical composition Pb9As4S15. Gratonite was discovered in 1939 at the Excelsior Mine, Cerro de Pasco, Peru. It is named in honor of geologist L. C. Graton (1880–1970), who had a long-standing association with the Cerro de Pasco mines.

References

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