igneous
Weathered quartz-rich rock, possibly granite or pegmatite
Granite/pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica or iron oxides
AI-generated identification · may be incorrectCoarse, irregular specimen with white-gray quartz/feldspar, pink-orange iron staining, and dark inclusions; likely Mohs 6–7, vitreous to dull luster, no obvious cleavage in quartz but feldspar cleavage may occur. Exact identification requires a fresh surface, hardness, and acid tests.
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Physical properties
Coarse, irregular specimen with white-gray quartz/feldspar, pink-orange iron staining, and dark inclusions; likely Mohs 6–7, vitreous to dull luster, no obvious cleavage in quartz but feldspar cleavage may occur. Exact identification requires a fresh surface, hardness, and acid tests.
Formation & geological history
Likely crystallized slowly from silica-rich magma, potentially as a pegmatitic vein; apparent oxidation and weathering occurred near the surface. Its precise age and locality cannot be determined from the image.
Uses & applications
Common granite is used as dimension stone, aggregate, countertops, and monuments; pegmatitic material is collected for crystals and may host feldspar, quartz, mica, or gemstones.
Geological facts
Quartz-rich rocks commonly show irregular fracture and resist scratching by steel, while feldspar is softer and cleaves. Pink coloration commonly reflects potassium feldspar or iron staining.
Field identification & locations
Look for interlocking visible grains, quartz’s glassy appearance, and feldspar’s blocky cleavage; acid fizz would suggest carbonate rather than granite. Common worldwide, especially in continental crust and granitic mountain belts.
