My watch list
my.chemeurope.com  
Login  

Mafic



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 micas, augite and the calcium-rich plagioclase feldspars. Common mafic rocks include basalt and gabbro.

Additional recommended knowledge

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 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, sideromelane, palagonite

See also

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Mafic". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE