metamorphic
Polished jasper–quartz pebble
Silica-rich microcrystalline quartz (SiO₂), likely brecciated jasper with milky quartz/chalcedony
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque burgundy-red, brown, gray, and white zones; dull to waxy in jasper and vitreous in quartz. No visible cleavage, conchoidal fracture, and likely specific gravity around 2.6.
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Physical properties
Hardness about 6.5–7 Mohs; opaque burgundy-red, brown, gray, and white zones; dull to waxy in jasper and vitreous in quartz. No visible cleavage, conchoidal fracture, and likely specific gravity around 2.6.
Formation & geological history
Formed when silica-rich groundwater filled fractures or replaced volcanic rock, producing iron-stained jasper and later quartz/chalcedony veins; the rounded shape is from stream or beach abrasion. Exact geological age and locality cannot be determined from the image.
Uses & applications
Used as a tumbled stone, cabochon, ornament, or lapidary material; rarely used industrially because of its small size and attractive pattern.
Geological facts
The red coloration commonly comes from hematite or other iron oxides, while the white area is quartz or chalcedony. The smooth surface appears naturally water-worn or mechanically polished.
Field identification & locations
Identify by its opaque red-brown silica matrix, contrasting white quartz, glassy-to-waxy luster, and resistance to scratching; common in volcanic terrains, gravel bars, and beaches. A steel file should not easily scratch it.
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