Black crystal aggregates of the very rare tellurium mineral benleonardite from the type locality in Moctezuma (Moctezuma Mine, Sonora, Mexico), with a contrasting white matrix. — Photo: David Hospital · CC BY-SA 4.0
Benleonardite
Benleonardite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Ag₁₅Cu(Sb,As)₂S₇Te₄.
It crystallizes in the tetragonal crystal system. It is a member of the Polybasite structural group.
Key properties: specific gravity 7.76.
IMA symbol Bln, IMA status: approved, named in 1985.
Found in fractures in an intensely silicified rhyolitic vitrophyre (Moctezuma mine, Mexico); in a limestone-hosted disseminated Au–Ag–Te deposit (Mayflower mine, Montana, USA).
It is found associated with Silver, acanthite, hessite, cervelleite, pyrite, sphalerite, dolomite, quartz (Moctezuma mine, Mexico); tetrahedrite, hessite, gold.
The name refers to Dr. Benjamin Franklin Leonard (1921–), of the U.S. Geological Survey, Denver, Colorado, USA.