Yellow Jasper

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Mustardy yellow to golden brown; Luster: Waxy to dull; Crystal structure: Microcrystalline/Cryptocrystalline; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.6-2.9.

Formation & Geological History

Formed through the accumulation of silica-rich fluids in volcanic ash or sedimentary deposits, often during the late-stage hydrothermal process. The yellow color is caused by the inclusion of goethite or other iron oxihydroxides.

Uses & Applications

Commonly used for lapidary work including cabochons, beads, and carvings. Often used in metaphysical practices, ornamental decoration, and as a durable material for stone tools in prehistoric times.

Geological Facts

Jasper is an opaque variety of chalcedony. The name 'jasper' comes from the Greek word 'iaspis', meaning 'spotted stone'. It was one of the stones used in the breastplate of High Priests in ancient times.

Field Identification & Locations

Identify in the field by its opacity (even on thin edges), its yellow-brown color, and its ability to scratch glass. It is commonly found in riverbeds or desert regions of the Western United States, Brazil, and India.

Identified on: 5/2/2026

Mode: Standard