A dark coloured, coarse-grained, igneous rock consisting of essential diopside (making up about 50% of the rock), alkali feldspar, and biotite, with or without olivine and/or nepheline. Where olivine or nepheline is abundant the rock name is prefixed with these mineral names (e.g. olivine-shonkinite). Shonkinites are essentially a type of alkali syenite.
Subjects: Earth Sciences and Geography.