igneous
Granite (likely granitic gneiss or granodiorite)
Granitoid; chiefly quartz, feldspar, and biotite/hornblende
AI-generated identification · may be incorrectFine- to medium-grained, speckled gray-green and cream, with a granular texture and vitreous to dull luster. Quartz and feldspar are Mohs 6–7; no obvious cleavage is visible at this scale, and density is typically 2.6–2.8 g/cm³.
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Physical properties
Fine- to medium-grained, speckled gray-green and cream, with a granular texture and vitreous to dull luster. Quartz and feldspar are Mohs 6–7; no obvious cleavage is visible at this scale, and density is typically 2.6–2.8 g/cm³.
Formation & geological history
Formed when silica-rich magma cooled slowly deep in Earth’s crust, commonly during Precambrian to Phanerozoic mountain-building events. The rounded surface indicates natural weathering or stream abrasion.
Uses & applications
Used as crushed aggregate, dimension stone, paving, and building material; attractive pieces may be collected as pocket specimens. This small rounded specimen has minimal commercial value.
Geological facts
The contrasting light minerals and dark mafic grains are characteristic of granitoid rocks. Exact identification would require a fresh surface, hand lens, and possibly mineral or chemical testing.
Field identification & locations
Look for interlocking visible grains of translucent quartz, pale feldspar, and black biotite or hornblende; granite is not layered and does not fizz with dilute hydrochloric acid. Common worldwide in continental shields and mountain belts.
