igneous
Weathered pegmatitic granite
Granite/pegmatite, chiefly quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, pale cream to gray rock with visible quartz and feldspar, mica-rich sparkling surfaces, and rusty iron-oxide staining; hardness about 6–7 Mohs, vitreous to pearly luster, no strong cleavage as a whole.
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Physical properties
Coarse-grained, pale cream to gray rock with visible quartz and feldspar, mica-rich sparkling surfaces, and rusty iron-oxide staining; hardness about 6–7 Mohs, vitreous to pearly luster, no strong cleavage as a whole.
Formation & geological history
Formed when silica-rich magma cooled slowly deep underground, allowing large crystals to grow; the specimen is strongly weathered, likely exposing a pegmatitic or granitic vein of Precambrian to younger age.
Uses & applications
Used as crushed aggregate, dimension stone, countertops, and architectural stone; attractive quartz- or feldspar-rich pieces may have modest collecting value.
Geological facts
The granular interlocking texture and pale feldspar distinguish it from most sedimentary rocks; orange-brown colors commonly result from oxidation of iron-bearing minerals.
Field identification & locations
Common in continental crust, especially granite batholiths and pegmatite districts worldwide. Field identification relies on visible quartz, feldspar, and mica grains; a glassy quartz grain scratches glass, while feldspar shows cleavage.
