sedimentary

Jasper (Iron-stained)

Silicon Dioxide (SiO2) with iron oxide inclusions

Hardness: 6.5-7 (Mohs scale); Color: Dark green to black with yellow/brown iron veins; Luster: Waxy to dull (tumble-smooth); Crystal structure: Microcrystalline/Cryptocrystalline hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9

Hardness: 6
Color: Dark green to black with yellow/brown iron veins
Luster: Waxy to dull (tumble-smooth)

Identified April 12, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water solutions into cracks or cavities in other rocks, or within volcanic ash beds. The colors come from iron and other mineral impurities present during the sedimentary process over millions of years.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), or as decorative 'pocket stones' and tumbled collectibles.

Geological facts

Jasper is an opaque variety of chalcedony. It has been used for ornamentation and tools since the Neolithic period. The specific specimen shown is a water-worn or tumbled cobble with distinct quartz/iron mineral veins.

Field identification & locations

Identify in the field by its smoothness (if found in rivers), lack of visible grains, and extreme hardness (it will scratch glass). Often found in riverbeds, glacial deposits, and coastal beaches.

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