igneous
Likely quartz-rich granitic rock
Granite or granitic pegmatite; mainly quartz (SiO₂) with feldspar and minor mica
AI-generated identification · may be incorrectSmall, rough, tan-gray specimen with granular texture and pale quartz/feldspar; likely Mohs hardness 6–7, vitreous-to-dull luster, massive rather than distinctly cleaved, and specific gravity about 2.6–2.7. Identification is uncertain because the image is distant and lacks a fresh broken surface.
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Physical properties
Small, rough, tan-gray specimen with granular texture and pale quartz/feldspar; likely Mohs hardness 6–7, vitreous-to-dull luster, massive rather than distinctly cleaved, and specific gravity about 2.6–2.7. Identification is uncertain because the image is distant and lacks a fresh broken surface.
Formation & geological history
Forms when silica-rich magma cools slowly deep within Earth, producing interlocking crystals; its exact geological age cannot be determined visually and may range from Precambrian to recent intrusive bodies.
Uses & applications
Common granitic material is used for crushed stone, construction aggregate, countertops, monuments, and decorative stone; this small piece has little commercial value unless unusually attractive or pegmatitic.
Geological facts
Granite is defined by abundant quartz and alkali feldspar, whereas visually similar weathered rhyolite or quartzite can be difficult to separate without testing.
Field identification & locations
Look for visible interlocking quartz and feldspar grains, lack of foliation, and a scratch resistance near that of steel; a streak, acid test, hand lens, and fresh surface would improve identification. Common worldwide in continental crust and exposed plutons.
