igneous
Small gray-green pebble, likely granite or granitic gneiss
Probable quartz–feldspar–mica aggregate; exact identification requires a closer view or testing
AI-generated identification · may be incorrectCoarse, speckled gray-green appearance with a dull to slightly crystalline luster; likely Mohs hardness 6–7, no obvious cleavage at this scale, and specific gravity around 2.6–2.7. Individual quartz and feldspar grains may be present.
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Physical properties
Coarse, speckled gray-green appearance with a dull to slightly crystalline luster; likely Mohs hardness 6–7, no obvious cleavage at this scale, and specific gravity around 2.6–2.7. Individual quartz and feldspar grains may be present.
Formation & geological history
If granite, it formed when silica-rich magma slowly cooled underground, commonly during Precambrian to Mesozoic crustal events; if gneiss, later metamorphism produced banding or grain recrystallization. The specimen may be a weathered, transported river or glacial pebble.
Uses & applications
Granite is widely used as aggregate, building stone, paving, countertops, and monuments; small pieces are mainly educational or decorative. It has little jewelry value unless unusually attractive or containing distinctive minerals.
Geological facts
Granite commonly contains interlocking quartz, feldspar, and mica crystals, giving it high durability. The image is insufficient to distinguish granite from gneiss, diorite, or another weathered crystalline rock.
Field identification & locations
Look for visible interlocking grains, quartz that does not scratch with a steel knife, and feldspar or mica flakes; a streak test is generally white. Common worldwide, especially in continental mountain belts and exposed shield regions.
