igneous
Tumbled gray-blue stone, likely quartz-rich feldspar or granite pebble
Probable granitic fragment: quartz (SiO₂) with feldspar and minor mica; exact identification requires testing
AI-generated identification · may be incorrectHardness approximately 6–7, pale gray to blue-gray, opaque, with a dull-to-waxy tumbled luster and fine granular texture; cleavage is not evident because it is polished. Specific gravity likely 2.6–2.7.
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Physical properties
Hardness approximately 6–7, pale gray to blue-gray, opaque, with a dull-to-waxy tumbled luster and fine granular texture; cleavage is not evident because it is polished. Specific gravity likely 2.6–2.7.
Formation & geological history
Likely weathered from an intrusive igneous rock formed by slow cooling of silica-rich magma, commonly Precambrian to younger; tumbling is human processing rather than geological formation.
Uses & applications
Used mainly as a decorative tumbled stone, craft material, or low-cost collectible; it has little jewelry value unless confirmed as a desirable gemstone such as larimar or moonstone.
Geological facts
The image alone cannot reliably distinguish feldspar, quartz, granite, or a dyed/coated stone. A glass-scratch test, streak test, magnification, and specific-gravity measurement would improve identification.
Field identification & locations
Look for visible quartz-feldspar grains, feldspar cleavage, and lack of reaction to dilute acid; common sources include river gravels and crushed-stone deposits worldwide. Avoid scratching valuable surfaces during testing.
