Foidite

Foidolite ( /ˈfɔɪdəlaɪt/) is a rare coarse-grained intrusive igneous rock with a feldspathoid mineral content greater than 60%. 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.