Nepheline
Image: <a rel="nofollow" class="external text" href="https://www.mindat.org/user-11235.html">Modris Baum</a> (Public domain)
Mineral NameNepheline
Chemical Formula(Na,K)AlSiO4
Mohs Hardness5.5
Crystal Systemhexagonal
Lustervitreous
Streak Colorwhite
Cleavagepoor/indistinct on {1010} and {0001}
Fractureconchoidal
Specific Gravity2.6
Colorswhite, gray, colorless
Transparencytranslucent
Type LocalityPoudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada
Mineral GroupSilicates
Usesceramic industry, glass manufacturing, collector
Associated Mineralskentbrooksite, sodalite, aegirine, arfvedsonite
Rarityuncommon
Description
The image displays a grayish-white, translucent Nepheline crystal, appearing somewhat blocky, nestled among a vibrant cluster of smaller, sparkling pink Kentbrooksite crystals within a darker matrix.
Geological Context
Nepheline is a feldspathoid mineral typically found in silica-undersaturated igneous rocks, such as nepheline syenites, phonolites, and some alkaline basalts, forming during the crystallization of magmas poor in silica.
