igneous
Weathered gray granitic rock
Granite, likely quartz–feldspar–mica aggregate
AI-generated identification · may be incorrectTypically Mohs 6–7, with a granular texture, gray color, pale quartz/feldspar, and dark mica or hornblende; vitreous to dull luster, no consistent cleavage as a whole, and specific gravity about 2.6–2.7.
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Physical properties
Typically Mohs 6–7, with a granular texture, gray color, pale quartz/feldspar, and dark mica or hornblende; vitreous to dull luster, no consistent cleavage as a whole, and specific gravity about 2.6–2.7.
Formation & geological history
Granite forms when silica-rich magma slowly crystallizes deep in continental crust, commonly during Precambrian to Phanerozoic mountain-building events; this piece shows surface weathering and iron staining.
Uses & applications
Used extensively as dimension stone, countertops, monuments, paving, and aggregate; attractive polished pieces can be decorative or collectible but this small specimen has little commercial value.
Geological facts
Its visible grains indicate slow cooling rather than volcanic eruption. Orange-brown patches commonly result from oxidation of iron-bearing minerals or weathered feldspar.
Field identification & locations
Identify it by interlocking visible grains of quartz, feldspar, and dark minerals; it should not fizz with dilute hydrochloric acid and will scratch glass. Common worldwide, especially in continental shields and mountain belts.
