Foidolite
![Foidolite (sodalitolite variety) from Namibia](/Images/godic/202501/13/Na-bl0614.jpg")
![Thin section of foidolite under polarizing microscope. In the foreground there is a large yellow sodium pyroxene grain surrounded by fine grains.](/Images/godic/202501/13/One_cannot_conquer_alone0614.jpg")
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.