sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Deep mahogany brown to reddish-brown; Luster: Dull or waxy; Crystal structure: Microcrystalline/cryptocrystalline (trigonal); Cleavage: None; Specific gravity: 2.58-2.91.

Hardness: 6
Color: Deep mahogany brown to reddish-brown
Luster: Dull or waxy

Identified April 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of fine-grained silica in sedimentary environments or by replacement of volcanic ash with silica during hydrothermal activity. Often found as rounded pebbles in stream beds or glacial till after weathering out of original host rock.

Uses & applications

Commonly used as a gemstone for jewelry (cabochons), interior decoration, ornamental carvings, and by collectors as a lapidary material for tumbling/polishing.

Geological facts

The name 'Jasper' is derived from a Persian word meaning 'spotted or speckled stone.' It is a member of the chalcedony family and has been used since antiquity for seals and amulets.

Field identification & locations

Identify in the field by its high hardness (it will scratch glass), opaque nature even on thin edges, and conchoidal (shell-like) fracture. Found worldwide, frequently in riverbeds and on beaches.