sedimentary

Biggs Jasper (Picture Jasper)

Silicon Dioxide (SiO2) - Opaque Silicified Volcanic Ash

Hardness: 6.5–7 on Mohs scale; Color: Tan, brown, and blue-grey; Luster: Waxy to vitreous; Crystal structure: Microcrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.6–2.9.

Hardness: 6
Color: Tan, brown, and blue-grey
Luster: Waxy to vitreous

Identified March 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of volcanic ash in freshwater lakes during the Miocene epoch (approx. 10–15 million years ago). Subsequent silicification by silica-rich groundwater preserved the layered patterns as the ash petrified.

Uses & applications

Primarily used in lapidary arts for cabochons, jewelry, and ornamental display pieces. Highly valued by collectors for its landscape-like banding.

Geological facts

Biggs Jasper is considered one of the 'classic' picture jaspers and was first discovered in the Biggs Junction area of Oregon during road construction in the 1960s. The 'pictures' are actually fossilized layers of mud and ash.

Field identification & locations

Identify by its distinct 'scenic' or layered banding that resembles desert landscapes. Found specifically in the Pacific Northwest, USA. Collectors look for high-contrast layers and 'blue sky' (the grey-blue centers).

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