sedimentary

Black Jasper (Black Stone / River Pebble)

Silicon Dioxide (SiO₂), Opaque variety of Chalcedony

AI-generated identification · may be incorrect

Hardness: 6.5–7 on Mohs scale. Color: Deep black to dark grey. Luster: Vitreous to waxy. Crystal Structure: Hexagonal/Trigonal (microcrystalline). Cleavage: None (Conchoidal fracture). Specific Gravity: 2.5–2.9.

Hardness: 6
Color: Deep black to dark grey
Luster: Vitreous to waxy

Identified February 5, 2026More sedimentary →

Explore Black Jasper (Black Stone / River 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 through the infiltration of silica-rich fluids into volcanic or sedimentary rocks. The black coloration is often due to the presence of manganese oxides or carbonaceous materials (organic matter). It is often found as water-worn pebbles in riverbeds or beaches.

Uses & applications

Used primarily for balancing energy and protection in metaphysical circles, as well as in jewelry (cabochons, beads), decorative stone garden accents, and lapidary arts.

Geological facts

Black Jasper is sometimes referred to as 'Basanite' particularly when it is used by jewelers as a 'touchstone' to test the purity of gold and silver based on the color of the streak left behind.

Field identification & locations

Identify by its heavy weight, lack of external grain, and its ability to take a very high polish. It will generally feel cool to the touch and cannot be scratched by a steel knife. Frequently found in regions with ancient volcanic activity or gravel deposits.