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Felsic identification and geology

Describing igneous rocks or magmas rich in light-colored minerals such as quartz, feldspar, and muscovite, typically with silica content greater than 63%. Felsic rocks are generally lighter in color, lower in density, and higher in viscosity when molten than mafic rocks. Common felsic rocks include granite, rhyolite, granodiorite, and dacite. The term derives from "feldspar" and "silica." Field: petrology. Example: The Sierra Nevada batholith is predominantly felsic in composition, consisting of granodiorite and granite with abundant quartz and feldspar, giving it its characteristic light gray color.. Related terms: Mafic, Intermediate, Granite, Silicic.

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:41.999576+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Felsic mean in geology?
Describing igneous rocks or magmas rich in light-colored minerals such as quartz, feldspar, and muscovite, typically with silica content greater than 63%. Felsic rocks are generally lighter in color, lower in density, and higher in viscosity when molten than mafic rocks. Common felsic rocks include granite, rhyolite, granodiorite, and dacite. The term derives from "feldspar" and "silica."
What is an example of Felsic?
The Sierra Nevada batholith is predominantly felsic in composition, consisting of granodiorite and granite with abundant quartz and feldspar, giving it its characteristic light gray color.
Which earth-science field uses the term Felsic?
Felsic is used in petrology.
Which terms are related to Felsic?
Related terms in this reference are Mafic, Intermediate, Granite, Silicic.

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