sedimentary

Banded Chert / Jasper

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Yellow-brown with white/tan banding, Luster: Waxy to dull, Crystal Structure: Microcrystalline/Cryptocrystalline (Trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.7

Hardness: 6

Identified June 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains or chemical precipitation in marine environments, often associated with Precambrian or Paleozoic sedimentary basins.

Uses & applications

Primarily used for lapidary work, jewelry (cabs and beads), tool making (historically for arrowheads), and as decorative landscaping gravel.

Geological facts

This specimen displays prominent sedimentary bedding or banding; such stones were frequently used by early humans for lithic tools due to their predictable fracturing and sharp edges.

Field identification & locations

Identify by its waxy luster, hardness (will scratch glass), and the visible layers or bands. Found globally in riverbeds, glacial deposits, and sedimentary outcrops.