Outstanding pale blue crystals of the very rare cadmium mineral aldridgeite (IMA 2010-019) from one of the only three known localities worldwide: Kelly Mine, Magdalena, Socorro County, New Mexico, United States of America. — Photo: David Hospital · CC BY-SA 4.0
Aldridgeite
Aldridgeite is an IMA-recognized mineral species in the sulfate class, with the chemical formula (Cd,Ca)(Cu,Zn)₄(SO₄)₂(OH)₆·3H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Devilline structural group.
Key properties: Mohs hardness 3; specific gravity 3.25; Pale blue streak; Vitreous luster; optically biaxial.
IMA symbol Adg, IMA status: approved, named in 2010.
Secondary mineral in the oxidation zone of a galena, Cd-bearing sphalerite, and chalcopyrite deposit.
It is found associated with Neidermayrite, pyromorphite.
The mineral was named to honor Edward William Aldridge, owner of the Duke of Cornwall Hotel, Broken Hill.