sedimentary
Jasper
Jasper (Silicon Dioxide, SiO2)
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 More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
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.
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.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone (Quartz-rich)
Arenite (SiO2)
sedimentary
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary