Peretaite , Klebelsbergite , Stibnite Locality: Pereta Mine, Pereta, Scansano , Grosseto Province , Tuscany , Italy ( Locality at mindat.org ) Size: 2.7 x 1.8 x 0.8 cm. Two very rare antimony sulfates are found in a rich vug between mirror-bright stibnite blades on this excellent combination thumbnail from the Type Locality for peretaite - the Pereta Mine in Tuscany, Italy. Sprays of tabular peretaite blades and sprays of acicular klebelsbergite crystals fill the vug. The accompanying label from noted rarities dealer, Gunnar Farber, also indicates stibiconite and kermesite crystals on this fine combination specimen. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Klebelsbergite
Klebelsbergite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Sb³⁺₄O₄(SO₄)(OH)₂.
It crystallizes in the orthorhombic crystal system (space group Pca2_1). It is a member of the Klebelsbergite structural group.
Key properties: specific gravity 4.62; White to yellow streak; Vitreous to silky luster; optically biaxial.
IMA symbol Kbb, IMA status: approved, named in 1929.
An alteration product of stibnite in antimony deposits.
It is found associated with Stibnite, valentinite, cervantite, kermesite, stibiconite, coquandite, peretaite, onoratoite, cetineite.
The mineral was named to honor Kunó Klebelsberg (1875–1932), Hungarian Minister of Education.