camptonite

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camptonite A dark-coloured, medium-grained igneous rock composed of plagioclase feldspar, barkevikite (a sodium-bearing amphibole) and/or augite. Camptonites are one variety of a group of intrusive rocks collectively known as lamprophyres which characteristically form dykes. The original camptonite was named from Campton Falls in New Hampshire, USA.

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