igneous
Tumbled feldspar-rich stone (likely granite or pegmatite fragment)
Potassium feldspar, chiefly orthoclase or microcline (KAlSi₃O₈), possibly mixed with quartz
AI-generated identification · may be incorrectCream to tan, opaque, with irregular reddish-brown iron staining and a polished/tumbled surface; feldspar hardness is about 6–6.5 Mohs, vitreous to slightly dull luster, and two cleavage directions. The visible grain size is too obscured to confirm the exact rock.
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Physical properties
Cream to tan, opaque, with irregular reddish-brown iron staining and a polished/tumbled surface; feldspar hardness is about 6–6.5 Mohs, vitreous to slightly dull luster, and two cleavage directions. The visible grain size is too obscured to confirm the exact rock.
Formation & geological history
Likely formed by slow cooling of silica-rich magma in a granite or pegmatite body, typically Precambrian to younger depending on locality. Iron oxidation produced the tan-brown staining.
Uses & applications
Commonly sold as a low-cost lapidary or craft stone and used decoratively; feldspar-bearing granite is also used for countertops, aggregate, and ceramics. This small piece has little commercial value.
Geological facts
Its rounded shape indicates tumbling or natural abrasion rather than a fresh crystal face. The cream color and cleavage-like patches are consistent with feldspar, but the photograph cannot exclude calcite or weathered quartzite.
Field identification & locations
Look for flat cleavage surfaces, hardness sufficient to scratch glass, and absence of fizzing in dilute hydrochloric acid; strong fizz would suggest calcite instead. Comparable feldspar-rich rocks occur worldwide in granitic terrains.
