igneous
Weathered granite pebble
Granite, composed mainly of quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, mottled tan-gray-brown, with a dull to slightly granular luster and no obvious cleavage as a whole; individual feldspar grains are Mohs 6, quartz about 7, and specific gravity about 2.6–2.7.
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Physical properties
Coarse-grained, mottled tan-gray-brown, with a dull to slightly granular luster and no obvious cleavage as a whole; individual feldspar grains are Mohs 6, quartz about 7, and specific gravity about 2.6–2.7.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in continental crust, commonly during Precambrian to Phanerozoic mountain-building events; this rounded specimen was likely shaped by stream or shoreline abrasion and weathering.
Uses & applications
Used extensively as building stone, countertops, monuments, aggregate, and landscaping material; small attractive pieces have modest specimen value.
Geological facts
The pinkish grains are likely potassium feldspar, gray translucent grains quartz, and darker patches biotite or amphibole. Surface brown coloration commonly reflects iron-oxide weathering.
Field identification & locations
Identify it by visible interlocking light and dark crystals and a speckled texture; unlike sandstone, it lacks cemented layers, and unlike basalt, it is lighter and visibly coarse-grained. Common worldwide, especially in continental shields and mountain belts.
