igneous
Weathered quartz-rich rock, possibly pegmatite
Likely quartz–feldspar pegmatite; exact identification is uncertain from the image
AI-generated identification · may be incorrectSmall, rough, irregular specimen with pale gray, cream, and purple-brown patches and a few visible crystalline grains. Likely hardness around 6–7 Mohs if quartz-rich; crystal structure and cleavage cannot be determined reliably from the photo.
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Physical properties
Small, rough, irregular specimen with pale gray, cream, and purple-brown patches and a few visible crystalline grains. Likely hardness around 6–7 Mohs if quartz-rich; crystal structure and cleavage cannot be determined reliably from the photo.
Formation & geological history
Pegmatite forms when water-rich residual magma crystallizes slowly, producing interlocking coarse minerals; its age depends on the source intrusion and cannot be inferred here.
Uses & applications
Similar material is collected as a geological specimen; pegmatite can also be a source of feldspar, quartz, mica, and gemstones.
Geological facts
The apparent cavity and discoloration may result from weathering or mineral alteration, but the image does not reveal a diagnostic feature.
Field identification & locations
Quartz and feldspar grains suggest pegmatite, but a close-up or simple hardness and streak tests would help distinguish it from other weathered rocks. Pegmatites occur worldwide, especially in granitic regions.
