sedimentary

Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Reddish-brown, earthy; Luster: Glossy to dull/waxy; Crystal Structure: Microcrystalline (trigonal); Cleavage: None/Conchoidal fracture.

Hardness: 6
Color: Reddish-brown, earthy
Luster: Glossy to dull/waxy

Identified March 17, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Reddish-brown, earthy; Luster: Glossy to dull/waxy; Crystal Structure: Microcrystalline (trigonal); Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed from silica-rich fluids and volcanic ash deposits that permeate porous rocks or replace organic matter over millions of years, often occurring in volcanic or sedimentary environments.

Uses & applications

Used primarily in lapidary arts for jewelry, beads, and cabochons. Historically used for making stone tools and ornaments.

Geological facts

Jasper is an opaque variety of chalcedony. The red color is typically caused by inclusions of hematite (iron oxide). It has been a popular gemstone since ancient times and is mentioned in various historical and religious texts.

Field identification & locations

Identify in the field by its hardness (will scratch glass), opaque nature, and smooth, curved (conchoidal) fracture surfaces. Commonly found in riverbeds and desert environments such as the American Southwest and India.