Nepheline
WordNet
noun
(1) A whitish mineral consisting of sodium aluminum silicate or potassium aluminum silicate in crystalline form; used in the manufacture of ceramics and enamels
WiktionaryText
Noun
nepheline
- A feldspathoid mineral of silica-poor igneous, plutonic and volcanic rocks. Chemically, Nepheline is a plagioclase feldspar with insufficient silica to satisfy the chemical bonds. Because of the unfilled bonds, Nepheline weathers rapidly and can only be seen as inclusions in freshly broken rock.
- Physical properties:
- Moh's Hardness: 5.5-6.0
- Specific gravity: 2.5-2.6
- Color: Colorless, white, gray, reddish, smoky; transparent to translucent
- Fracture: Subconchoidal
- Cleavage: Good prismatic
- Habit: Hexagonal-Hexagonal pyramidal
- Fluorescence: Often orange-red in portions of crystals