mineral

Jasper (Red Jasper)

Jasper (Silicon Dioxide, SiO2)

Hardness: 6.5–7 on Mohs scale; Color: Reddish-brown due to iron inclusions; Luster: Dull to vitreous; Crystal Structure: Microcrystalline trigonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91

Hardness: 6
Color: Reddish-brown due to iron inclusions
Luster: Dull to vitreous

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments, often during hydrothermal activity or tectonic deposition. It is found in deposits ranging from Precambrian to more recent geological eras.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and carvings. Historically used for making tools (scrapers, arrowheads) due to its hardness and conchoidal fracture. Also popular in jewelry and metaphysical collecting.

Geological facts

Jasper is an opaque variety of chalcedony. The red color specifically comes from high iron content. It has been used since antiquity in Sumerian, Egyptian, and Minoan cultures for seal stones and amulets.

Field identification & locations

Identify in the field by its opacity (unlike translucent agate), red color, and smooth 'waxy' water-worn surface if found in riverbeds. Common in the Western United States (Oregon, Idaho), South Africa, and Brazil. It should be hard enough to scratch glass.