sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: Red, brown, yellow, mottled; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Red, brown, yellow, mottled
Luster: Vitreous to dull

Identified April 19, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 Mohs; Color: Red, brown, yellow, mottled; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Formation & geological history

Formed through the deposition of silica from water solutions or volcanic ash in sedimentary environments. Often occurs as nodules or in veins, frequently associated with iron oxides which provide the coloration.

Uses & applications

Used primarily for gemstones, ornamental carvings, jewelry, lapidary art, and historical weapon making (flaking toolstone).

Geological facts

Jasper has been used by humans for thousands of years; it was a favorite gem in the ancient world and is even mentioned in the Bible. The name comes from the Greek 'iaspis', meaning spotted stone.

Field identification & locations

Identify in the field by its high hardness (scratches glass), waxy to dull luster, and lack of translucency compared to agate. Commonly found in riverbeds, deserts, and volcanic regions worldwide.