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Formula: Sb8O11Cl2
Chloride, antimony-bearing mineral, alteration product of
stibnite
Crystal System: Monoclinic
Specific gravity: 5.3 measured, 5.49 calculated
Hardness: 3
Streak: White
Colour: White
Solubility: Insoluble in water, completely soluble in 6N hydrochloric acid
Environments
Localities
At the type locality, Le Cetine di Cotorniano Mine, Chiusdino, Siena Province, Tuscany, Italy, onoratoite occurs
as needle-like crystals on stibnite, sometimes with an intermediate layer of
stibiconite. It is an oxidation product of
stibnite in an antimony deposit in
highly silicified evaporites. Associated minerals include stibnite,
stibiconite, cetineite,
peretaite, klebelsbergite and
quartz
(MM 36.1037-1044).
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