Cowlesite FOV: 5.9 x 4.3 mm Locality: Four Mile Quarry, Porter, Grays Harbor Co., Washington, USA Description: Thanks to Ralph Thomas. MOB coll — Photo: Modris Baum · Public domain
Cowlesite
A zeolite named for American mineralogist John Cowles, first described from roadcuts near Goble, Oregon.
Intro adapted from Wikipedia (CC BY-SA).
Cowlesite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca(Al₂Si₃)O₁₀·5-6H₂O.
It crystallizes in the orthorhombic crystal system.
Key properties: specific gravity 2.14; Pearly luster; optically biaxial.
IMA symbol Cow, IMA status: approved, named in 1975.
Found in cavities in basalts and scoria, typically the only zeolite within a single vesicle.
It is found associated with Zeolites, apophyllite.
The mineral was named to honor John Cowles (1907–1985), amateur mineralogist of Rainier, Oregon, USA.