sedimentary

Jasper and Yellow Chert (Tumbled)

Microcrystalline Quartz (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Red/Brown (Jasper) and Yellow/Orange (Chert); Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7

Hardness: 6
Color: Red/Brown (Jasper) and Yellow/Orange (Chert)
Luster: Vitreous to waxy

Identified March 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the accumulation of silica-rich fluids in sedimentary environments or volcanic ash cavities. These specific specimens show signs of 'tumbling' or mechanical polishing, smoothing their natural rough edges over geologic time or via a rock tumbler.

Uses & applications

Used primarily in lapidary arts, jewelry (beads, cabochons), and as decorative landscaping stones. Highly valued in historical crafts for tool-making due to sharp fracture edges.

Geological facts

Jasper gets its red color from iron inclusions, specifically hematite. Chert and Jasper are essentially the same material, with names varying based on impurities and opacity. They have been used since the Stone Age for flaking into arrowheads and scrapers.

Field identification & locations

Identify in the field by their extreme hardness (they will scratch glass) and smooth, waxy feel when wet. Often found in riverbeds, glacial tills, or coastal beaches. For collectors, look for unique patterns or banding.

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