Sedimentary

Jasper (Iron-stained Quartzite/Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Rusty orange, brown, and yellow-tan; Luster: Dull to waxy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9.

Hardness: 6
Color: Rusty orange, brown, and yellow-tan
Luster: Dull to waxy

Identified February 20, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Rusty orange, brown, and yellow-tan; Luster: Dull to waxy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9.

Formation & geological history

Formed through the accumulation of silica-rich sediments in aqueous environments, often during the Proterozoic or Paleozoic eras. The rounded shape suggests fluvial transport (water erosion) over a long period.

Uses & applications

Used primarily as decorative lawn stone, in lapidary work for cabochons, and historically for making stone tools due to its hardness and sharp fracture edges.

Geological facts

Jasper is an opaque variety of chalcedony. The reddish-brown coloration in this specimen is caused by the oxidation of iron (rusting) within the mineral matrix.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel knife), smooth water-worn texture, and dense, opaque appearance. Commonly found in riverbeds and glacial tilling across North America.