Nepheline

 

A rock-forming mineral, nepheline is common in silica-deficient igneous rocks. Discovered in 1801 in the lavas of Mount Vesuvius, Italy, this mineral is characterized by its greasy luster. The name comes from the Greek word meaning “a cloud” because when immersed in acid, the mineral becomes cloudy.

Mineral Photos courtesy of R.Weller/Cochise College