sedimentary

Iron-rich chert or jasper

Microcrystalline quartz (SiO₂), colored by hematite/goethite inclusions

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque reddish-brown, with a dull to waxy luster and conchoidal fracture; crystal grains are microscopic. The specimen appears fine-grained and iron-stained, though its small size limits certainty.

Identified August 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica-rich sediment or chemically precipitated silica lithifies and becomes colored by iron oxides; occurrences range from Precambrian to recent sedimentary environments. Commonly found as resistant pebbles in gravel, streambeds, and glacial deposits.

Uses & applications

Used as decorative stone, lapidary material, aggregate, and historically for tools; attractive pieces may be polished into cabochons or beads.

Geological facts

Jasper is an opaque variety of chert, and its red coloration commonly comes from hematite. It can resemble red volcanic rock, brick fragments, or slag.

Field identification & locations

Look for uniform microtexture, very high hardness, lack of visible pores, and a glassy/conchoidal break; it should scratch ordinary glass but not be scratched by a steel knife. Common in gravel deposits worldwide.