sedimentary

Jasper pebble

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5–7 on Mohs scale; Color: Reddish-brown common due to iron inclusions; Luster: Dull to vitreous; Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Reddish-brown common due to iron inclusions
Luster: Dull to vitreous

Identified March 24, 2026More sedimentary →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through the deposition of silica from water or within volcanic ash flows. This specimen shows significant river-worn rounding, indicating transport in a high-energy water environment. While jasper can be any age, many deposits are from the Mesozoic or Paleozoic eras.

Uses & applications

Commonly used in lapidary work for cabochons and beads, as well as industrial abrasives or aquarium gravel. Often collected as decorative pocket stones.

Geological facts

Jasper is an opaque variety of chalcedony. In antiquity, red jasper was associated with vitality and used extensively in seals and amulets across Mesopotamia and Egypt.

Field identification & locations

Identify in the field by its opacity (it will not let light through even at thin edges, unlike agate), smooth water-worn surface, and inability to be scratched by a steel knife. Commonly found in stream beds, beaches, and gravel pits.