sedimentary

Yellow Jasper

Cryptocrystalline quartz (SiO2) with iron inclusions

AI-generated identification · may be incorrect

Hardness: 6.5–7 (Mohs scale); Color: Yellow to mustard-brown; Luster: Dull to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Yellow to mustard-brown
Luster: Dull to waxy

Identified March 27, 2026More sedimentary →

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Physical properties

Hardness: 6.5–7 (Mohs scale); Color: Yellow to mustard-brown; Luster: Dull to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Formation & geological history

Formed through the infiltration of silica in sedimentary or volcanic rock layers, where it crystallizes with high iron oxide content into a dense, opaque microcrystalline quartz. Often found as water-worn pebbles in stream beds or coastal areas.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and tumbled stones. Historically used for ornaments and seals; also used in decorative landscaping and as an ornamental stone in jewelry.

Geological facts

Jasper is known as the 'supreme nurturer' in various cultures and has been used for thousands of years. The yellow color specifically comes from Goethite or other iron hydroxide inclusions within the silica matrix.

Field identification & locations

Identify in the field by its opacity (unlike translucent agate) and its smooth, rounded, waxy texture when tumbled by water. Found globally but common in regions like the Western USA, Madagascar, and Russia. It will not be scratched by a steel knife.