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 on {1010} and {0001}
Fractureconchoidal
Specific Gravity2.6
Colorswhite, gray, colorless, yellowish, greenish, reddish
Transparencytransparent
Type LocalityPoudrette quarry (De-Mix quarry; Demix quarry; Uni-Mix quarry; Carrière Mont Saint-Hilaire; MSH), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada
Mineral GroupSilicates
Usesindustrial (ceramics, glass), collector
Associated Mineralskentbrooksite, sodalite, cancrinite, aegirine, arfvedsonite
Rarityuncommon
Description
The image displays numerous small, translucent to transparent, pinkish-red, hexagonal prismatic crystals of nepheline, with the largest crystal measuring 0.8 mm, embedded within a lighter matrix.
Geological Context
Nepheline is a feldspathoid mineral typically found in silica-undersaturated igneous rocks, such as nepheline syenites, phonolites, and other alkaline rocks, often forming in plutonic or volcanic environments.
