Nepheline
ID: 126
Nepheline
Chemical Formula
(Na,K)AlSiO4
Hardness (Mohs)
5.5-6
Crystal System
Hexagonal
Streak
White
Luster
Vitreous to greasy
Diaphaneity
Transparent to translucent
Color
White, grey, yellowish, brownish, greenish, reddish
Crystal Habit / Mode of Occurrence
Hexagonal prisms, often short and stout; massive, granular
Fun Facts
Nepheline is a feldspathoid, meaning it's a feldspar-like mineral that forms in silica-poor rocks.