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Mafic is a term used in geology for silicate minerals, magmas, and rocks which have relatively high concentrations of the heavier elements. The term is a combination of "magnesium" and "ferric," the Latin word for iron, but mafic magmas also are rich in calcium and sodium.

Mafic minerals are usually dark in color and have specific gravities greater than 3. Common rock-forming mafic minerals include olivine, pyroxene, amphibole, biotite and other micas, augite and the plagioclase feldspars. Common mafic rocks include basalt and gabbro.

In terms of chemistry, mafic rocks are on the other side of the rock spectrum from the so-called felsic rocks.

Rock TextureName of Mafic Rock
PegmatiticGabbro pegmatite
Coarse grained (phaneritic)Gabbro
Coarse grained and porphyriticPorphyritic gabbro
Fine grained (aphanitic)Basalt
Fine grained and porphyriticPorphyritic basalt
PyroclasticBasalt tuff or breccia
VesicularVesicular basalt
AmygdaloidalAmygdaloidal basalt
Many small vesiclesScoria
GlassyTachylyte or palagonite