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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.
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 The term is no longer current as it is incorrectly based on the idea that silicic acid is the chief form of silicon in rocks.
FelsiteFelsite is a very fine to cryptocrystalline igneous rock that may or may not contain larger crystals, called phenocrysts, that are typical of many porphyritic igneous rocks. The mass of the rock consists of a fine-grained matrix of felsic materials, parti is a petrologicPetrology is a field of geology which focuses on the study of rocks and the conditions by which they form. There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary. Igneous petrology focuses o field term used to refer to very fine grained light colored volcanic rocks that may be later reclassified after more detailed microscopic or chemical analysis.
| Rock Texture | Name of Felsic Rock |
| Pegmatitic | Granite pegmatitePegmatite is a very coarse-grained igneous rock that has a grain size of 20 mm or more; such rocks are referred to as pegmatitic''. Most pegmatites consist of granite that contains quartz, feldspar and mica. Pegmatites are important because they often con |
| 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 |
| Vesicular | None |
| Amygdaloidal | None |
| Many small vesicles | Pumice |
| Glassy | Obsidian |
See also: List of minerals and List of rocks
Petrology