Jasper (Green Jasper/Chert)

Physical Properties

Hardness: 6.5–7 on Mohs scale; Color: olive green with reddish-brown oxidation veins; Luster: waxy to vitreous; Crystal structure: Microcrystalline (Trigonal); Cleavage: none (conchoidal fracture); Specific gravity: 2.58–2.91

Formation & Geological History

Formed through the deposition of silica from water-saturated solutions or via the accumulation of radiolarian tests in deep marine environments. This specimen shows signs of river or water smoothing, creating its rounded edges.

Uses & Applications

Commonly used for lapidary work, cabochons, polished decorative stones, and historical utility as strike-a-lights or flint tools.

Geological Facts

Green jasper was used in antiquity as a medicine for symptoms ranging from stomach issues to snakebites and was highly prized in the ancient world for seal stones.

Field Identification & Locations

Identify in the field by its hardness (cannot be scratched by a steel knife) and waxy, smooth surface. Often found in riverbeds, gravel pits, or ocean beaches.

Identified on: 4/28/2026

Mode: Standard