gemstone

Tumbled jasper or agate

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

AI-generated identification · may be incorrect

Small polished, rounded translucent-to-opaque pebble with gray, cream, yellow-brown, and reddish patches. Quartz hardness is about 7 Mohs, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage; density is approximately 2.6 g/cm³.

Identified August 16, 2026More gemstone →

Explore Tumbled jasper or agate 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 groundwater filled cavities or fractures, later incorporating iron oxides and other impurities that produced the mottled colors. The exact geological age cannot be determined from the photograph; such material occurs in rocks ranging from Paleozoic to recent deposits.

Uses & applications

Used for cabochons, beads, tumbled stones, jewelry, and decorative objects; common pieces have modest value.

Geological facts

The specimen appears more likely to be jasper-rich chalcedony than a single pure mineral, though the image is insufficient for precise identification.

Field identification & locations

Identify by its glassy/waxy polish, quartz-like hardness, rounded tumbled form, and resistance to scratching by steel; a scratch test should be avoided on finished jewelry. Common sources include Brazil, India, Madagascar, Mexico, and the western United States.