metamorphic

Tumbled banded stone, likely gneiss or granite

Quartz–feldspar rock, possibly banded gneiss; exact identification requires testing

AI-generated identification · may be incorrect

Hardness approximately 6–7 Mohs; rounded and polished, with pale pink/cream feldspar, dark gray-black mineral banding, granular texture, and mostly dull-to-satin luster. Visible banding suggests aligned biotite or amphibole rather than a single mineral crystal.

Identified September 11, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed from high-grade metamorphism of an igneous protolith, causing mineral segregation into bands; such rocks are commonly Precambrian to Paleozoic, though the specimen’s age cannot be determined visually.

Uses & applications

Used primarily as a decorative tumbled stone, paperweight, or craft material; larger gneiss and granite are used for countertops, paving, monuments, and building stone.

Geological facts

The dark stripe may be biotite mica, hornblende, or a mafic seam. A fresh scratch or thin section would distinguish gneiss from banded granite, quartzite, or other mixed silicate rocks.

Field identification & locations

Commonly found in continental shield and mountain-belt terrains, including Scandinavia, Canada, the northeastern United States, India, and Brazil. Look for interlocking grains, feldspar’s pink tint, and true compositional banding; streak, acid, and hardness tests help confirm it.