Definition of ferromagnesian in US English:



  • (of a rock or mineral) containing iron and magnesium as major components.

    • ‘There are two types of silicate minerals, the ferromagnesian and the nonferromagnesian silicates.’
    • ‘The very low magnesium content of Lime Crest ferroaxinite may reflect the relative scarcity of ferromagnesian minerals in the granite.’
    • ‘The example from the granite at Lime Crest quarry is very low in magnesium relative to those found in rocks containing more ferromagnesian minerals.’
    • ‘The rhombohedral phase usually occurs as large tabular inclusions near the rims of ferromagnesian phenocrysts.’
    • ‘Thus, in magma chambers dense ferromagnesian minerals may sink to form cumulate rocks at the base of the chamber, whereas in partial melting a lower-density melt may percolate upwards.’