sedimentary

Chert (Jasper)

Microcrystalline Quartz (SiO2) with Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown to orange-brown; Luster: Waxy to dull; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Reddish-brown to orange-brown
Luster: Waxy to dull

Identified May 4, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown to orange-brown; Luster: Waxy to dull; Crystal structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Formation & geological history

Formed by the precipitation of silica from groundwater or as a replacement of organic material such as limestone. The red/orange hue indicates high iron oxide content. It can range from Precambrian to recent geological ages.

Uses & applications

Used historically for stone tools (arrowheads), modern lapidary work (jewelry, beads), and as heavy-duty landscaping material.

Geological facts

Red jasper was highly prized in antiquity and mentioned in many historical texts, including the Bible and Greek mythology, as a stone of protection and endurance.

Field identification & locations

Identify by its conchoidal (shell-like) fracture, intense hardness (cannot be scratched by a steel knife), and opaque waxy appearance. Commonly found in river beds or sedimentary outcrops.