English edit

Etymology edit

ultra- +‎ mafic

Adjective edit

 
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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 edit

Noun edit

ultramafic (plural ultramafics)

  1. A rock with such properties.