Platy pink crystal aggregates of the very rare tellurium mineral spiroffite from the type locality. Associated mineral is yellow tellurite. Spiroffite has only been found in 3 localities worldwide. From: Bambollita Mine, Moctezuma, Sonora, Mexico. Analyzed specimen. — Photo: David Hospital · CC BY-SA 4.0
Spiroffite
Spiroffite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn²⁺₂Te⁴⁺₃O₈.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: Mohs hardness 3.5; specific gravity 5.01; White streak; Adamantine luster; optically biaxial.
IMA symbol Spf, IMA status: approved, named in 1962.
Very rare in the oxidized zone of an Au–Te deposit (Moctezuma mine, Mexico); very rare in intensely silicified pyritic shales (Joe mine, Arizona, USA).
It is found associated with Tellurium, tellurite, paratellurite, denningite, mroseite, zemannite (Moctezuma mine, Mexico).
The mineral was named to honor Professor Kiril Spiroff (1901–1981), Bulgarian–American mineralogist, Michigan College of Mining and Technology, Houghton, Michigan, USA.