sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Red, yellow, brown, often mottled; Luster: Dull to waxy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red, yellow, brown, often mottled
Luster: Dull to waxy

Identified April 12, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Red, yellow, brown, often mottled; Luster: Dull to waxy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Formation & geological history

Formed through the deposition of silica-rich fluids within volcanic or sedimentary environments. Impurities like iron oxide create the distinct red and yellow colors. Most specimens are from the Phanerozoic eon.

Uses & applications

Used primarily in lapidary arts, jewelry (cabochons), interior decoration, and as a semi-precious collector stone.

Geological facts

Jasper is an opaque variety of chalcedony. Historically, it was believed to provide protection and was worn by ancient warriors to ensure courage and success in battle.

Field identification & locations

Identify by its opacity (it will not let light through even at thin edges) and its smooth, shell-like fracture pattern. Commonly found in riverbeds and desert environments globally.