sedimentary

Iron-stained jasper/chert fragment

Microcrystalline quartz (SiO₂), likely hematite/goethite-bearing jasper

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; reddish-brown, gray, and cream colors with earthy to slightly waxy luster, opaque appearance, and no visible cleavage. The angular fragment shows conchoidal-looking fracture and porous iron-oxide staining.

Identified August 20, 2026More sedimentary →

Explore Iron-stained jasper/chert fragment in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Likely formed when silica-rich groundwater replaced or cemented sediment, with iron oxides producing the red-brown coloration; exact age and locality cannot be determined from the photograph. Jasper and chert occur in many sedimentary terrains, commonly from Precambrian through younger rocks.

Uses & applications

Used as ornamental stone, cabochons, beads, carvings, and lapidary material; historically, chert was used for cutting tools and fire-starting. This small rough fragment has mainly educational or decorative value.

Geological facts

Jasper is an opaque variety of chalcedony or microcrystalline quartz, and its colors commonly reflect hematite, goethite, clay, or other inclusions.

Field identification & locations

Test: it should scratch glass and resist a steel knife; a streak test may show little color, while strong reddish powder suggests iron oxides. Common sources include the western United States, Australia, India, Brazil, and many other regions.