Jasper

Physical Properties

Hardness: 6.5 - 7 on Mohs scale; Color: Reddish-brown to orange-tan; Luster: Vitreous to waxy; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58 - 2.91

Formation & Geological History

Formed from the deposition of silica from volcanic ash or water circulation, often in sedimentary environments. Iron inclusions Provide the red/brown coloring. Formation can occur across various geological ages from Precambrian to recent.

Uses & Applications

Commonly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a collector specimen. Historically used for making tools and weapons due to its hardness and sharp conchoidal fracture.

Geological Facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning spotted stone. It has been a popular gemstone since antiquity and was mentioned in the Bible and other ancient texts.

Field Identification & Locations

Look for a smooth, waxy texture and shell-like (conchoidal) fractures. It will scratch glass but cannot be scratched by a steel knife. Common in gravel beds, riverbanks, and desert regions globally.

Identified on: 4/15/2026

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