sedimentary

Ferruginous Jasper (or Hemlithos)

Silicon Dioxide (SiO2) with Iron Oxide inclusions (Fe2O3)

Hardness: 6.5-7 (Mohs); Color: Rusty red, brown, and ochre with dark gray or black metallic inclusions; Luster: Dull to vitreous; Crystal Structure: Microcrystalline (trigonal); Cleavage: None (conchoidal fracture).

Hardness: 6
Luster: Dull to vitreous

Identified July 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the process of sedimentation and silicification where silica-rich fluids permeate iron-rich deposits. It is often found in Banded Iron Formations dating back to the Precambrian era (over 2 billion years ago).

Uses & applications

Used primarily as a lapidary material for cabochons, beads, and decorative carvings. It is also a popular specimen for amateur geologists due to its distinct color.

Geological facts

The red color is caused by hematite or goethite. In ancient times, jasper was often referred to as the 'great nurturer' and was believed to provide physical protection during travel.

Field identification & locations

Identify in the field by its high hardness (will scratch glass), heavy weight for its size due to iron content, and typical opaque, earthy red appearance. Commonly found in areas with ancient iron deposits like the Lake Superior region or Australia.

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