sedimentary

Tumbled jasper or chert pebble

Microcrystalline quartz (SiO₂), likely jasper/chert

AI-generated identification · may be incorrect

Opaque tan-golden body with darker brown rind and subtle mottling; dull to waxy luster, conchoidal fracture, no visible cleavage, Mohs hardness about 6.5–7, and specific gravity near 2.6. The smooth rounded surface indicates natural abrasion or tumbling.

Identified September 21, 2026More sedimentary →

Explore Tumbled jasper or chert pebble in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed when silica-rich fluids replaced or cemented sediments, producing microcrystalline quartz; its exact geological age cannot be determined from the photograph. Commonly occurs as durable river, beach, or glacial gravels.

Uses & applications

Used for cabochons, beads, carvings, lapidary specimens, and decorative stone; generally unsuitable for major construction because pieces are small.

Geological facts

Jasper is an opaque variety of chert colored by iron oxides and other impurities. The tan coloration likely reflects limonite or hematite staining.

Field identification & locations

Identify it by its opaque fine-grained texture, hardness, waxy surface, and lack of cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include gravel beds and silica-rich volcanic or sedimentary terrains.