Nepheline syenite

Nepheline syenite
Igneous rock
Two photos of a broken, brown rock
Hand samples of nepheline syenite of the Ordovician Beemerville Complex, northern New Jersey
Composition
Primaryalkali feldspar, nepheline, clinopyroxene, amphibole, biotite
Secondarymagnetite, ilmenite, apatite, titanite

Nepheline syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar.[1] The rocks are mostly pale colored, grey or pink, and in general appearance they are not unlike granites, but dark green varieties are also known. Phonolite is the fine-grained extrusive equivalent.

  1. ^ Kresten, Peter; Troll, Valentin R. (2018). "The Alnö Carbonatite Complex, Central Sweden". GeoGuide. doi:10.1007/978-3-319-90224-1. ISBN 978-3-319-90223-4. ISSN 2364-6497. S2CID 135266142.

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