Valentinite Locality: Djebel Nador, Constantine Province , Algeria ( Locality at mindat.org ) Picture width 5 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Valentinite
Orthorhombic antimony oxide — radiating prismatic crystals of 'antimony bloom', the oxidation product of stibnite.
Intro adapted from Wikipedia (CC BY-SA).
Valentinite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Sb₂O₃.
It crystallizes in the orthorhombic crystal system (space group Pccn).
Key properties: Mohs hardness 2.5–3; specific gravity 5.76; White streak; Adamantine, pearly on cleavages luster; refractive index 2.293; optically biaxial.
IMA symbol Vln, IMA status: approved, named in 1845.
An alteration product of antimony-bearing minerals in the oxidized zone of hydrothermal antimony deposits.
It is found associated with Stibnite, antimony, stibiconite, cervantite, kermesite, tetrahedrite.
The mineral was named to honor Basilius Valentinus, 15th century alchemist, who early wrote concerning antimony.