sedimentary

Yellow Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Mustard yellow to golden brown; Luster: Dull to greasy (vitreous when polished); Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Mustard yellow to golden brown
Luster: Dull to greasy (vitreous when polished)

Identified April 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the precipitation of silica from volcanic fluids or through the silicification of sedimentary minerals. Its distinct yellow color is caused by iron (goethite or limonite) inclusions during the solidification process.

Uses & applications

Used primarily as a gemstone for jewelry, lapidary projects (cabochons), and ornamental carvings. It is also a popular specimen for collectors and practitioners of holistic therapy.

Geological facts

Yellow Jasper is known for its high iron content. Throughout history, it has been carried by travelers as a protective amulet. It is a variety of Chalcedony, but unlike Agate, it is opaque rather than translucent.

Field identification & locations

Identify by its opacity, mustard-like color, and conchoidal fracture. In the field, look for smooth, waxy surfaces on broken faces. It is commonly found in riverbeds or volcanic regions globally, including parts of the USA (Oregon, Idaho), India, and Madagascar.