sedimentary

Green Jasper (Chert)

Microcrystalline Quartz (SiO2) with iron/clay inclusion

Hardness: 6.5-7 on Mohs scale. Color: Pale sage green to olive green with iron oxide (orange-brown) staining and faint banding. Luster: Waxy to sub-vitreous, silky when smooth. Cleavage: None (shows conchoidal fracture). Specific Gravity: ~2.65.

Hardness: 6
Luster: Waxy to sub-vitreous, silky when smooth

Identified July 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the precipitation of silica-rich fluids in low-temperature metamorphic or hydrothermal environments, often incorporating fine-grained iron silicate minerals (such as celadonite or chlorite) that impart the soft green hue.

Uses & applications

Popular among rockhounds for tumbling, cabochon cutting, lapidary art, and decorative polished stones. Also used historically for tools due to its sharp conchoidal fracturing.

Geological facts

Green jasper is often associated with beach stones found along the Pacific Northwest coast (such as Oregon and Washington) and California. The reddish-orange patches are caused by localized oxidation of iron minerals (limonite/hematite).

Field identification & locations

Identified by its high hardness (cannot be scratched by a steel knife), smooth waxy feel, opaque transparency, and characteristic green color with faint banding. Commonly found in river beds, gravel deposits, and ocean beaches.

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