rhyolite
Sign in to saveRhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.
AI overview
Rhyolite is a volcanic rock that contains more silica than any other volcanic rock type and typically has a glassy or fine-grained appearance, though it can sometimes contain larger crystals embedded within finer material. It is the surface-erupted version of granite and is primarily made up of quartz, sanidine, and plagioclase minerals.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Rock.name
- Rhyolite
- Rock.type
- Igneous
- Rock.image
- Loebejuener porphyr poliert.jpg
- Rock.composition
- Quartz and alkali feldspar (sanidine and sodic plagioclase)
- Rock.composition_secondary
- Biotite and hornblende
- Rock.class
- Felsic
- Rock.texture
- Glassy or aphanitic, sometimes porphyritic
- Rock.equivalent
- Granite of intrusive equivalent
via Wikipedia infobox
Article
9 sectionsContents
- Description
- Geology
- Petrogenesis
- Occurrence
- Name
- Uses
- See also
- References
- External links
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.
Its high silica content makes rhyolitic magma extremely viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations.