Picture width 2.3 mm. Collection and photograph Christian Rewitzer. PXRD confirmed. From Chuquicamata Mine, Chuquicamata District, Calama, El Loa Province, Anto — Photo: Christian Rewitzer · CC BY-SA 3.0
Antlerite
A green hydrous copper sulfate once thought rare but now known as a major mineral of the oxidized zones of copper mines, including Chile's Chuquicamata.
Intro adapted from Wikipedia (CC BY-SA).
Antlerite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Cu²⁺₃(SO₄)(OH)₄.
It crystallizes in the orthorhombic crystal system (space group Pnma).
Key properties: Mohs hardness 3.5; specific gravity 3.88; typically green; Pale green streak; Vitreous luster; refractive index 1.751; optically biaxial.
IMA symbol Atl, IMA status: approved, named in 1889.
Uncommon, typically formed in the oxidized zone of copper deposits under highly acid conditions, especially in arid regions.
It is found associated with Brochantite, atacamite, chalcanthite, kröhnkite, natrochalcite, linarite, gypsum.
The name refers to the Antler mine, Arizona, USA, where the first specimens were collected.
Collections: Collector Favorites.