Description
The mineral clinoptilolite (CAS number 12173-10-3) is a hydrated sodium-potassium-calcium-aluminum silicate with the chemical formula (Na,K,Ca)2-3Al3(Al,Si)2Si13O36·12(H2O). This tecto-silicate belongs to the zeolites. The transparent, colorless, white, or red clinoptilolite has a vitreous luster, a white streak color, and perfect cleavage along the crystal plane [010]. Clinoptilolite has an average density of 2.15 and a hardness of 3.5 to 4. The crystal system is monoclinic, and the mineral's radioactivity is barely measurable. Its gamma ray value, according to the American Petroleum Institute, varies between 21.89 and 95.03, depending on the mineral's precise chemical composition. The name of the mineral clinoptilolite is derived from the Greek word clinos ("slanting") and ptilolite, another name for the mineral mordenite, which clinoptilolite closely resembles. Clinoptilolite is a fairly common mineral that occurs primarily as a devitrification product in silica-bearing volcanic glass from tuffs. It also occurs in fissures in rhyolites, andesites, and basalts. The type localities are a basalt from a ridge near Hoodoo Mountain, Wyoming, USA, and an offshore drill hole in Japan.
