sedimentary

Jasper

Silicon dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Variegated brown, tan, and dark black; Luster: Dull to waxy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Variegated brown, tan, and dark black
Luster: Dull to waxy

Identified April 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into sediment or volcanic ash, often containing iron oxides that provide its color. These specimens can range in age from millions to hundreds of millions of years old.

Uses & applications

Used primarily as decorative lapidary stones, in jewelry making (cabochons), and as a collector's item due to its unique patterns.

Geological facts

Jasper is an opaque variety of chalcedony. The name 'jasper' is derived from the Greek word 'iaspis', meaning 'spotted stone.' It has been used by ancient civilizations for amulets and tools.

Field identification & locations

Identify by its hardness (it will scratch glass), lack of transparency, and smooth, water-worn texture if found near rivers. Often found in gravel beds or mountain regions where silica-rich rocks have weathered.