Zunyite, Tintic District, East Tintic Mountains, Utah, USA. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Zunyite
A complex aluminium silicate with a unique 13-aluminium cage — tiny glassy tetrahedra in altered volcanic rock.
Intro adapted from Wikipedia (CC BY-SA).
Zunyite is an IMA-recognized mineral species in the silicate class, with the chemical formula Al₁₃Si₅O₂₀(OH,F)₁₈Cl.
It crystallizes in the cubic crystal system (space group F-43m).
Key properties: Mohs hardness 7; specific gravity 2.874; typically colorless or white or gray or yellow; white streak; Vitreous luster; refractive index 1.596; optically isotropic.
IMA symbol Zun, grandfathered status — known before the IMA’s founding, named in 1884.
Found in highly aluminous shales and hydrothermally altered volcanic rocks.
It is found associated with Pyrophyllite, kaolinite, alunite, diaspore, rutile, pyrite, hematite, quartz.
The name refers to the Zu~ni mine, Colorado, USA, where it was discovered.
Collections: Collector Favorites, Rare & Remarkable.