Nepheline Replacement

Nepheline, a silica-undersaturated aluminosilicate, Na3KAl4Si4O16

Nepheline, Also Called Nephelite. T h a t O c c u rs I n I nt r u s i ve A n d Volcanic Rocks With Low Silica, And In Their Associated Pegmatites. It Is U s e d I n G l a s s A n d C e r a m i c M a n u f a c t u r i n g A n d O t h e r I n d u s t r i e s , A n d H a s B e e n I n v e s t i g a t e d A s A n O r e O f Aluminium.

Nepheline Is The Characteristic Mineral Of Alkaline Plutonic Rocks, Particularly Nepheline Syenites And Nepheline Gneisses. It Occurs In Beautiful Crystal Form With Mica, Garnet, And Sanidine Feldspar On Monte Somma, Vesuvius, Italy. For Detailed Physical Properties, See Feldspathoid (table).

Nepheline Appears Only In Quarz-free Alkaline Rocks In Association With Other Alkali-rich Or Silica-poor Minerals (other Feldspathoid, Naanphiboles, Na-pyroxenes). It Forms As A Primary Magmatic Minerals Through The Crystallization Of A Narich Si-poor Magmas; It May Result From The Assimilation Of Limestone By Basic Or Intermediate Magmas.

Nepheline