Jasper

Physical Properties

Hardness: 6.5-7 on the Mohs scale; Color: Reddish-brown due to iron oxide impurities; Luster: Dull or waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (Conchoidal fracture); Specific gravity: 2.58-2.91

Formation & Geological History

Usually forms from the deposition of silica from water-rich environments, often in volcanic or hydrothermal settings where fine-grained mineral materials become cemented. This sample appears water-worn, suggesting a secondary sedimentary deposition in a riverbed or shore.

Uses & Applications

Commonly used for lapidary work, jewelry (cabochons), talismans, and as decorative stone in mosaics or as ornamental pebbles.

Geological Facts

Jasper has been used throughout history; the 'Seal of the Prophets' in Islamic tradition was said to be an engraved jasper. It is an opaque variety of chalcedony.

Field Identification & Locations

Identify by its hardness (will scratch glass), opaque nature, and earthy, dull luster. It's commonly found in gravel beds, beaches, and desert areas worldwide.

Identified on: 4/30/2026

Mode: Standard