sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Opaque reddish-brown to orange-brown with green or grey inclusions. Luster: Vitreous to waxy. Crystal structure: Microcrystalline (trigonal). Cleavage: None (conchoidal fracture).

Hardness: 6
Luster: Vitreous to waxy

Identified May 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water-rich environments, often in volcanic ash or hydrothermal veins. Its color is derived from high iron oxide (hematite) content during formation.

Uses & applications

Used primarily in lapidary work for jewelry, cabochons, and decorative ornamental items. Historically used for making tools due to its hardness and sharp fracture edges.

Geological facts

Jasper has been used as a gemstone since antiquity. In many cultures, red-toned jasper was believed to be a stone of physical strength, vitality, and protection.

Field identification & locations

Identify in the field by its opacity (it will not let light through even at thin edges, unlike agate), its hardness (will scratch glass), and its smooth, waxy feel when tumbled or polished.