igneous
Polished/tumbled feldspar-rich rock, possibly granite or rhyolite
Likely quartz–feldspar aggregate; exact identification requires testing
AI-generated identification · may be incorrectHardness approximately 6–7 Mohs; mottled salmon-pink, gray, white, and dark brown, with a dull-to-glassy polished luster. The granular texture suggests interlocking feldspar and quartz crystals rather than a single mineral; cleavage may occur in feldspar.
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Physical properties
Hardness approximately 6–7 Mohs; mottled salmon-pink, gray, white, and dark brown, with a dull-to-glassy polished luster. The granular texture suggests interlocking feldspar and quartz crystals rather than a single mineral; cleavage may occur in feldspar.
Formation & geological history
Probably formed from cooling silica-rich magma, either as intrusive granite or volcanic rhyolite; age cannot be determined from the photograph. The rounded surface is human-tumbled or polished.
Uses & applications
Used mainly as a lapidary or decorative specimen; similar granite and rhyolite are used for countertops, aggregate, building stone, and ornamental objects. Jewelry value is generally modest.
Geological facts
Pink coloration commonly comes from potassium feldspar, while gray translucent areas may be quartz and dark patches biotite, amphibole, or iron oxides. A precise name requires a fresh surface, hardness testing, and ideally a thin section or mineral analysis.
Field identification & locations
Common worldwide, especially in continental crust and volcanic regions. Check for visible quartz, feldspar cleavage, and resistance to scratching by steel; an acid test is generally unnecessary.
