sedimentary

Jasper

Jasper (Cryptocrystalline Quartz; SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5–7 (Mohs scale); Color: Yellow, brown, and reddish tones with darker banding; Luster: Dull to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.91.

Hardness: 6
Color: Yellow, brown, and reddish tones with darker banding
Luster: Dull to waxy

Identified April 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water or through the hydrothermal replacement of minerals. Often found in association with sedimentary environments or volcanic ash deposits where silica-rich fluids permeate the ground.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons), interior decoration, and as a popular specimen for rock hounds and collectors.

Geological facts

Jasper is an opaque variety of silica. The various colors are usually due to the presence of iron inclusions; yellow and brown colors often indicate goethite or limonite content. It has been used for making tools and ornaments since prehistoric times.

Field identification & locations

Identify by its extreme hardness (cannot be scratched by a steel blade), opaque nature, and smooth, waxy feel when polished. It is commonly found in gravel beds, stream deposits, and rocky coastlines.