Jasper

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Reddish-brown, yellow, olive green; Luster: Vitreous to greasy; Crystal Structure: Microcrystalline/Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Formation & Geological History

Formed from the deposition of silica from water or hydrothermal fluids, often accumulating in sedimentary beds or as nodules in volcanic rocks. This specimen shows oxidation typical of surface weathering or iron oxide inclusion.

Uses & Applications

Used primarily in lapidary work for cabochons, beads, and architectural ornamentation. Historically used for making stone tools due to its sharp conchoidal fracture.

Geological Facts

Jasper has been used by ancient civilizations for thousands of years; it was a favorite gem in the ancient world and is mentioned in biblical texts. It is essentially an impure variety of silica containing up to 20% foreign materials which give it its colors.

Field Identification & Locations

Identify in the field by its hardness (it can scratch glass), lack of visible crystals, and its waxy or dull appearance when unpolished. Found worldwide in creek beds or areas with volcanic/sedimentary activity.

Identified on: 4/14/2026

Mode: Standard