sedimentary

Chert / Red Jasper

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale), Color: Reddish-pink to white/grey, Luster: Waxy to dull, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7

Hardness: 6

Identified May 6, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: Reddish-pink to white/grey, Luster: Waxy to dull, Crystal Structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7

Formation & geological history

Formed from the accumulation of silica-rich microfossils or precipitation from hydrothermal fluids in sedimentary basins. The red color suggests iron oxide impurities.

Uses & applications

Historically used for stone tools and arrowheads; currently used for lapidary work, jewelry, and collector specimens.

Geological facts

This specimen shows distinct conchoidal fracturing and iron-rich banding. Red varieties are often called jasper, which has been used in jewelry for thousands of years.

Field identification & locations

Look for smooth, waxy surfaces and curved, glass-like fractures. It will easily scratch glass but cannot be scratched by a steel knife. Common in ancient sedimentary beddings.