Erionite (FOV: 1.08 mm) Locality: Phelps Dodge Corporation Well No. 1, Little Ajo Mountains, Ajo District, Pima County, Arizona, USA Original description: 1.08 — Photo: Matteo Chinellato · CC BY-SA 3.0
Erionite-Ca
Also known as: Erionite.
The calcium-dominant erionite — a fibrous zeolite of altered volcanic ash, notorious for its asbestos-like health hazard.
Intro adapted from Wikipedia (CC BY-SA).
Erionite-Ca is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₅[Si₂₆Al₁₀O₇₂]·30H₂O.
It crystallizes in the hexagonal crystal system (space group P6_3/mmc). It is a member of the Erionite structural group.
Key properties: Mohs hardness 2–3; typically white or colorless or pink or gray; white streak; vitreous luster.
IMA symbol Eri-Ca, IMA status: approved, named in 1967.
Collections: Collector Favorites.