sedimentary

Jasper

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Primarily red, brown, and yellow; Luster: Dull to vitreous; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91.

Hardness: 6
Color: Primarily red, brown, and yellow
Luster: Dull to vitreous

Identified March 13, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of fine volcanic ash or silica-rich water permeating cracks in other rocks. It is often found in prehistoric sedimentary deposits, frequently dating back hundreds of millions of years (Paleozoic to Mesozoic eras).

Uses & applications

Commonly used as a gemstone in jewelry, for ornamental carvings, cabochons, and as a decorative stone in mosaics and interior flooring.

Geological facts

Jasper has been a favorite gemstone throughout history; it was mentioned in the Bible and utilized by the ancient Mesopotamians, Greeks, and Romans for seals and talismans. It is unique among quartz varieties due to its opacity caused by high levels of mineral impurities.

Field identification & locations

Identify in the field by its waxy to earthy appearance, high hardness (cannot be scratched by a steel knife), and characteristic smooth, shell-like fracture pattern. Common locations include riverbeds and alluvial deposits in territories like the Western US (Oregon, Idaho), India, Brazil, and Australia.