Foidolite
Foidolite ( /ˈfɔɪdəlaɪt/) is a rare 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.
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Foidolite (sodalitolite variety) from Namibia
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Thin section of foidolite under polarizing microscope. In the foreground there is a large yellow sodium pyroxene grain surrounded by fine grains.
Some foidolites are a potential source of aluminium.
See also
References
- Le Maitre, R.W. (editor) (2002). Igneous Rocks — A Classification and Glossary of Terms (2nd ed.). Cambridge: Cambridge University Press. pp. 4, 22, 24, 82. ISBN 0-521-66215-X.CS1 maint: extra text: authors list (link)
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