dolerite
Pronunciation: /ˈdɒlərʌɪt/
noun
- a dark, medium-grained igneous rock, typically with ophitic texture, containing plagioclase, pyroxene, and olivine. It typically occurs in dykes and sills. Also called diabase.
Origin:
mid 19th century: from French dolérite, from Greek doleros 'deceptive' (because it is difficult to distinguish from diorite)