mineral

Bicolor Quartz Pebble

Silicon Dioxide (SiO2) with mineral inclusions

Hardness: 7 on Mohs scale. Color: Translucent white/yellow (milky quartz) and opaque dark green/black (chlorite or iron inclusions). Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Luster: Vitreous to waxy

Identified March 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed from hydrothermal veins where silica-rich fluids cooled and crystallized. The bicolored appearance suggests a shift in mineral impurities during growth or the fusion of two different vein materials. It has been water-worn into a smooth pebble shape, likely over thousands of years in a river or coastal environment.

Uses & applications

Used primarily as decorative river rock, landscaping material, or a minor collector's item for those interested in stream-tumbled mineral specimens.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The dark portion of this specimen is likely due to the presence of chlorite, tourmaline, or actinolite inclusions which grew alongside the quartz crystals.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and its smooth, rounded 'potato' shape characteristic of water erosion. Found globally in riverbeds, beaches, and glacial till. Collectors look for sharp color boundaries like the one seen here.

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