English

Adjective

ultramafic ‎(comparative more ultramafic, superlative most ultramafic)

1. (geology) Describing igneous rocks that contain magnesium and iron and only a very small amount of silica, such as are found in the Earth’s mantle.

Synonyms

• ultrabasic

Noun

ultramafic ‎(plural ultramafics)

1. A rock with such properties.