From Academic Kids
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, oxygen, aluminium, sodium, 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, hornblende, orthoclase, and the sodium rich plagioclase feldspars. The most common felsic rock is granite.
Acid rock, such as granite, is igneous rock with over 60% by weight of silicon dioxide. The term is no longer current as it is incorrectly based on the idea that silicic acid is the chief form of silicon in rocks.
|Rock Texture||Name of Felsic Rock|
|Coarse grained (phaneritic)||Granite|
|Coarse grained and porphyritic||Porphyritic granite|
|Fine grained (aphanitic)||Rhyolite|
|Fine grained and porphyritic||Porphyritic rhyolite|
|Pyroclastic||Rhyolitic tuff or breccia|
|Many small vesicles||Pumice|