sedimentary

Tumbled jasper or chert pebble

Microcrystalline quartz (SiO₂), likely iron-stained jasper/chert

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; cream, tan, gray, and bluish coloration with diffuse dark veining; dull to waxy luster and no visible cleavage. The rounded, glossy surface indicates mechanical tumbling and polishing.

Identified September 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Jasper and chert form when silica-rich fluids replace or cement sediment, often with iron or manganese impurities producing the colors. Such material commonly formed in ancient marine or volcanic-sedimentary environments, ranging from Precambrian to younger ages.

Uses & applications

Used as an inexpensive lapidary stone for cabochons, beads, carvings, and decorative tumbled specimens; occasionally used for small ornamental objects.

Geological facts

The specimen’s exact variety cannot be confirmed from one photograph; it could also be a weathered quartz-rich pebble or brecciated jasper. Jasper is opaque, unlike translucent chalcedony or agate.

Field identification & locations

Identify by its very hard, opaque, fine-grained texture, waxy luster, and resistance to scratching by steel; quartz should not be scratched by a knife. Common sources include the western United States, Madagascar, Brazil, India, and Australia.