Black metallic crystal aggregate of the rare copper telluride weissite associated to also rare minoritary idaite from Winston, Sierra County, New Mexico, United States of America. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Idaite
Idaite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Cu₃FeS₄.
It crystallizes in the tetragonal crystal system (space group I-42m). It is a member of the Sphalerite, Stannite structural group.
Key properties: Mohs hardness 2.5–3.5; specific gravity 4.2; Metallic. Anisotropism: Strong, reddish orange to reddish brown. R1 –R2: (400) 13.9–17.7, (420) 14.8–18.5 luster.
IMA symbol Ida, grandfathered status — known before the IMA’s founding, named in 1958.
A lamellar decomposition product of bornite, commonly in association with fine spindles of chalcopyrite; apparently of secondary origin, a first product of enrichment.
It is found associated with Chalcopyrite, bornite, pyrite, sphalerite, chalcocite, pyrrhotite, mackinawite (Skouriotissa, Cyprus).
The name refers to the Ida mine in Namibia.