sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Reddish-brown with white quartz veining; Luster: Dull to vitreous when polished; Crystal structure: Microcrystalline/Cryptocrystalline (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Reddish-brown with white quartz veining
Luster: Dull to vitreous when polished

Identified June 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from silica-rich fluids percolating through sedimentary rocks or volcanic ash, often during the Proterozoic to Cenozoic eras. The red color is typically due to iron (hematite) inclusions.

Uses & applications

Used primarily in lapidary for jewelry (cabochons), ornamental carvings, and as a decorative stone in collecting and aquarium landscaping.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone'. In ancient times, it was believed to provide protection and healing properties.

Field identification & locations

Identify by its hardness (cannot be scratched by a steel nail), lack of translucency, and conchoidal (shell-like) fracture pattern. Commonly found in riverbeds and on beaches where harder silica stones collect after erosion.