sedimentary

Jasper and Chalcedony Nodule

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 7 on the Mohs scale. Color: Red (jasper core) surrounded by grey to brownish chalcedony margins. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.58-2.66.

Hardness: 7 on the Mohs scale
Luster: Waxy to vitreous

Identified August 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the precipitation of silica-rich fluids within cavities, voids, or fractures in host rocks, often associated with volcanic activity or sedimentary diagenesis over millions of years.

Uses & applications

Used for lapidary work, cabochons, ornamental carvings, decorative objects, and as a popular specimen for rock and mineral collectors.

Geological facts

This specimen displays a striking natural contrast between a red jasper center and a surrounding chalcedony rind, often referred to by rockhounds as a 'picture jasper' or composite quartz nodule.

Field identification & locations

Can be identified in the field by its distinct hardness (scratches glass), waxy luster, and concentric banding or color zoning. Commonly found in stream beds, volcanic regions, and desert environments worldwide.

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