sedimentary

Red Jasper (Siltstone or Chert-based Jasper)

Silicon dioxide with hematite (SiO2 + Fe2O3)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale; Color: Rusty red to brownish-red; Luster: Dull or waxy when unpolished, vitreous when polished; Crystal structure: Hexagonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91.

Hardness: 6
Color: Rusty red to brownish-red
Luster: Dull or waxy when unpolished, vitreous when polished

Identified April 11, 2026More sedimentary →

Explore Red Jasper (Siltstone or Chert-based Jasper) 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

Formed through the accumulation of fine silica grains and iron oxides. This specimen appears water-worn, likely from a stream or river bed where it was tumble-polished by natural water action over thousands of years.

Uses & applications

Used primarily in lapidary arts for making beads, cabochons, and decorative carvings. It is also a popular collector's stone for beginners and used in landscaping or aquarium decor.

Geological facts

Jasper is an opaque variety of chalcedony. The red color is specifically caused by high concentrations of iron inclusions. Historically, red jasper was known as a stone of endurance and was used by ancient civilizations for amulets and seals.

Field identification & locations

Identify in the field by its opacity (unlike translucent carnelian), its high hardness (it will scratch glass), and its smooth, waxy feel when wet. Often found in river gravels and deserts worldwide.