sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 Mohs; Color: Brown, red, or greenish-brown; Luster: Waxy to dull; Crystal structure: Microcrystalline/Cryptocrystalline quartz; Cleavage: None (conchoidal fracture); Specific gravity: 2.5-2.8

Hardness: 6
Color: Brown, red, or greenish-brown
Luster: Waxy to dull

Identified May 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains or chemical precipitation from groundwater within sedimentary rock layers. It is often found in nodules or as bedded deposits.

Uses & applications

Historically used for stone tools (arrowheads). Modernly used in jewelry, lapidary art, and as a decorative stone in landscaping.

Geological facts

Chert was one of the first materials used by early humans for fire-starting and tool-making due to its sharp edges when broken. Jasper is a variety of chert colored by iron impurities.

Field identification & locations

Identify by its 'shell-like' conchoidal fracture and its ability to scratch glass. It is commonly found in stream beds or within limestone and dolomite formations.