Foidolite

Foidolite (/ˈfɔɪdəlaɪt/) is a rare phaneritic (coarse-grained) intrusive igneous rock in which more than 60% (by volume) of light-coloured minerals are feldspathoids.

[1] Crystals of alkali feldspar, plagioclase, biotite, amphibole, pyroxene, and/or olivine may be present within the rock.

The volcanic equivalents are termed foidite and phonolitic or tephritic foidites.

Some foidolites are a potential source of aluminium.

This igneous rock-related article is a stub.

Foidolite ( sodalitolite variety) from Namibia
Thin section of foidolite under polarizing microscope. In the foreground there is a large yellow sodium pyroxene grain surrounded by fine grains.