Jasper

Physical Properties

Hardness: 6.5-7 on Mohs scale; Color: typically red, brown, or green; Luster: dull to vitreous; Crystal structure: Microcrystalline/Trigonal; Cleavage: none; Specific gravity: 2.58-2.91.

Formation & Geological History

Formed from the deposition of silica-rich fluids in sedimentary or volcanic environments, often associated with banded iron formations or volcanic ash. It can date back billions of years, famously in the Archean and Proterozoic eras.

Uses & Applications

Used primarily for jewelry, lapidary arts, and ornamental objects. Historically used for making tools and seals.

Geological Facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning 'spotted stone.' Many varieties are named after their appearance, such as Ocean Jasper or Picture Jasper.

Field Identification & Locations

Identify by its opacity, hardness (will not be scratched by a steel knife), and its characteristic conchoidal fracture. Commonly found in riverbeds, coastlines, and desert regions worldwide.

Identified on: 4/22/2026

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