mineral
Polished red-brown feldspar-rich stone, possibly sunstone or aventurine feldspar
Likely potassium feldspar (orthoclase/microcline), KAlSi₃O₈; exact identification requires testing
AI-generated identification · may be incorrectTypically Mohs 6–6.5, salmon-red to brown, vitreous to pearly luster, and blocky crystal structure with two good cleavages; the specimen appears smoothly tumbled and opaque to slightly translucent. Color may result from hematite or other iron inclusions.
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Physical properties
Typically Mohs 6–6.5, salmon-red to brown, vitreous to pearly luster, and blocky crystal structure with two good cleavages; the specimen appears smoothly tumbled and opaque to slightly translucent. Color may result from hematite or other iron inclusions.
Formation & geological history
Feldspar crystallizes in silica-rich igneous rocks such as granite and pegmatite as magma cools, generally during the Precambrian to Phanerozoic; later weathering produces rounded cobbles. The pictured piece may be a polished lapidary fragment rather than a natural crystal.
Uses & applications
Used mainly as a decorative or collectible stone; feldspar is also important industrially in ceramics, glass, and abrasives. If it has attractive aventurescence, it may be sold as sunstone or aventurine feldspar.
Geological facts
Its identity cannot be confirmed from appearance alone; a streak, hardness, cleavage, and refractive-index test would help distinguish it from quartz, jasper, or dyed agate.
Field identification & locations
Look for salmon color, flat cleavage surfaces, and hardness sufficient to scratch glass but not quartz; common sources include India, Madagascar, Norway, Oregon, and granite-rich regions worldwide. Avoid relying on color alone.
