Information About

Mafic




In and Sodium .

Mafic minerals are usually dark in color and have a Specific Gravity greater than 3. Common rock-forming mafic minerals include Olivine , Pyroxene , Amphibole , Biotite and other Mica s, Augite and the calcium-rich 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. The term roughly corresponds to the older ''basic'' rock class.

Mafic lava, before cooling, has a lower Viscosity than Felsic lava due to its lower silica content. Water and other volatiles can more easily and gradually escape from mafic lava, so eruptions of volcanoes made of mafic lavas are less explosively violent than felsic lava eruptions. Most mafic lava volcanoes are oceanic volcanoes, like Hawaii .













Rock Texture'''Name of Mafic Rock'''
Pegmatitic Gabbro Pegmatite
Coarse grained ( Phaneritic ) Gabbro
Coarse grained and Porphyritic Porphyritic Gabbro
Fine grained ( Aphanitic ) Basalt
Fine grained and porphyriticPorphyritic Basalt
Pyroclastic Basalt Tuff or Breccia
Vesicular Vesicular Basalt
Amygdaloidal Amygdaloidal Basalt
Many Small Vesicles Scoria
Glassy Tachylyte , Sideromelane , Palagonite



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