Nephelinite

Nephelinite lava (grey) containing a fragment of peridotite (yellow), Kaiserstuhl, Germany.

Nephelinite is a fine-grained or igneous rock made up mostly of nepheline and clinopyroxene (also augite).

Nephelinite is dark and may look like basalt in a hand. However, basalt consists mostly of augite and calcic.