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Felsic

Felsic is a term used in geology to refer to silicate minerals, magmas, and rocks which are enriched in the lighter elements, such as silica and oxygen, aluminum, and potassium. The term combines the words "feldspar" and "silica."

Felsic minerals are usually light in color and have specific gravities less than 3. Common felsic minerals include quartz, biotite, muscovite mica, hornblende and the orthoclase feldspars. The most common felsic rock is granite.

On the opposite side of rock spectrum are "mafic" rocks.

Rock TextureName of Felsic Rock
Pegmatitic[?]Granite pegmatite
Coarse grained (phaneritic[?])Granite
Coarse grained and porphyritic[?]Porphyritic granite
Fine grained (aphanitic[?])Rhyolite
Fine grained and porphyriticPorphyritic rhyolite
Pyroclastic[?]Rhyolitic tuff or breccia
Vesicular[?]None
Amygdaloidal[?]None
Many small vesicles[?]Pumice
Glassy[?]Obsidian

See also: List of minerals



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