Jasper

Physical Properties

Hardness: 6.5-7 (Mohs scale), Color: Reddish-brown to liver-red (due to iron inclusions), Luster: Vitreous to dull, Crystal structure: Trigonal/Microcrystalline, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.58-2.91

Formation & Geological History

Formed through the deposition of silica from water into cracks or volcanic ash, occurring in sedimentary beds or volcanic environments. Often found in areas with ancient volcanic activity where hydrothermal fluids have permeated the soil.

Uses & Applications

Used primarily for lapidary work, jewelry (cabochons), interior decoration, and as a collectible gemstone. 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.' Rare varieties like 'Ocean Jasper' or 'Orbicular Jasper' are highly prized by collectors for their unique patterns.

Field Identification & Locations

Identify in the field by its smooth, waxy texture when wet, conchoidal (shell-like) fracture patterns, and total opacity (light will not pass through even thin edges). It cannot be scratched by a steel knife.

Identified on: 4/24/2026

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