| diabase | <chemical> A basic, dark-coloured, holocrystalline, igneous rock, consisting essentially of a triclinic feldspar and pyroxene with magnetic iron; often limited to rocks pretertiary in age. It includes part of what was early called greenstone. Origin: F. Diabase, fr. Gr. A crossing or passing over, fr.; + to go; so called by Brongniart, because it passes over to diorite. Source: Websters Dictionary (01 Mar 1998) |
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