*** Welcome to piglix ***

Stibiconite

Stibiconite
Stibiconite.jpg
General
Category Oxide minerals
Formula
(repeating unit)
Sb3+Sb5+2O6(OH)
Strunz classification 4.DH.20
Crystal system Isometric
Crystal class Hexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space group Fd3m
Unit cell a = 10.27 Å; Z = 8
Identification
Formula mass 478.25 g/mol
Color Pale yellow to yellowish white, reddish white, orange; gray, brown, black when impure
Crystal habit Massive, botryoidal, as incrustations, powdery
Cleavage None
Fracture Clay-like
Mohs scale hardness 4-5
Luster Vitreous - dull
Streak light yellow
Diaphaneity Transparent to translucent
Specific gravity 4.1 - 5.8, Average = 4.94
Optical properties Isotropic
Refractive index n=1.6-1.97
References

Stibiconite is an antimony oxide mineral with formula: Sb3O6(OH). Its name originates from Greek "stibi" (antimony) and "konis" (powder), alluding to its composition and habit. It is a member of the pyrochlore super group.

It was first described in 1862 for an occurrence in the Brandholz - Goldkronach District, Fichtelgebirge, Franconia, Bavaria.

It occurs as a secondary alteration product of other hydrothermal antimony minerals such as stibnite. It occurs in association with cervantite, valentinite, kermesite, native antimony and stibnite.


...
Wikipedia

...