Jasper

Physical Properties

Hardness: 6.5–7 on Mohs scale; Color: Reddish-brown to earthy red; Luster: Dull to greasy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58–2.91

Formation & Geological History

Formed through the deposition of silica from mineral springs or hydrothermal vents into sedimentary or volcanic environments. Often associated with volcanic activity where silica-rich fluids permeate porous rock. It is typically millions of years old, often dating to various geological eras.

Uses & Applications

Used primarily as decorative gemstones, in jewelry (cabochons), as an ornamental stone in architecture, and as an abrasive in some industrial capacities.

Geological Facts

Jasper has been used by ancient civilizations for seals and talismans. Its red color is typically caused by iron (III) inclusions. It is a variety of chalcedony and is opaque, unlike the translucent carnelian.

Field Identification & Locations

Identify in the field by its opacity, conchoidal (shell-like) fracture, and hardness (it will scratch glass). Commonly found in river beds, beaches, and desert regions worldwide, notably in the western USA (Oregon, Idaho), Australia, and Brazil.

Identified on: 4/13/2026

Mode: Standard