metamorphic

Weathered quartz-rich metamorphic rock, possibly gneiss or quartzite

Quartz–feldspar–mica metamorphic aggregate; exact identification requires testing

AI-generated identification · may be incorrect

Gray, coarse-grained, weakly banded specimen with translucent quartz-rich zones and rusty yellow-brown iron-oxide staining. Quartz hardness is 7 Mohs; overall luster is vitreous to dull, with no obvious cleavage and variable specific gravity around 2.6–2.7.

Identified September 18, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when quartz-bearing sediment or igneous rock was altered by heat and pressure, with later weathering and oxidation along fractures. Its geological age cannot be determined from the photograph.

Uses & applications

Typically used as decorative stone, aggregate, or a teaching/collecting specimen; it has little jewelry value unless attractive areas can be cut and polished.

Geological facts

The pale brown coloration is probably limonite/goethite produced by oxidation of iron-bearing minerals. The rounded surface suggests stream transport or prolonged weathering rather than a fresh quarry face.

Field identification & locations

Look for interlocking grains, foliation or compositional banding, and a glassy quartz-rich fraction; a streak, hardness, and acid test would help distinguish quartzite from gneiss or altered granite. Similar rocks occur worldwide in metamorphic terrains.