ultramafic
English
Etymology
Adjective
ultramafic (comparative more ultramafic, superlative most ultramafic)
- (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
Noun
ultramafic (plural ultramafics)
- A rock with such properties.