sedimentary

Jasper / Chert Pebble

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on Mohs scale; Color: yellowish-brown, tan, to ochre; Luster: dull to waxy; Cleavage: none (conchoidal fracture); Specific Gravity: ~2.58 - 2.64

Hardness: 6
Color: yellowish-brown, tan, to ochre
Luster: dull to waxy

Identified October 5, 2026More sedimentary →

Explore Jasper / 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

Hardness: 6.5 - 7 on Mohs scale; Color: yellowish-brown, tan, to ochre; Luster: dull to waxy; Cleavage: none (conchoidal fracture); Specific Gravity: ~2.58 - 2.64

Formation & geological history

Formed through the precipitation of microcrystalline silica from solution in sedimentary environments, later rounded and naturally tumbled by water erosion in a stream, river, or coastal beach setting.

Uses & applications

Popular among rockhounds and collectors, especially when naturally shaped like hearts; historically used for knapping stone tools, and today used for tumbling, lapidary art, and pocket stones.

Geological facts

Naturally heart-shaped stones are formed entirely by coincidence through differential erosion, fracture along natural stress planes, and stream tumbling.

Field identification & locations

Identified by its microcrystalline texture, lack of visible grains, high hardness (scratches glass), and naturally smooth, water-worn exterior. Commonly found in gravel beds, rivers, and shores worldwide.