sedimentary

Hematite Nodules (Moqui Marbles style)

Iron Oxide (Fe2O3)

AI-generated identification · may be incorrect

Hardness: 5.5-6.5; Color: Metallic grey to black; Luster: Metallic to sub-metallic; Crystal structure: Trigonal; Specific gravity: 5.26

Hardness: 5
Color: Metallic grey to black
Luster: Metallic to sub-metallic

Identified July 6, 2026More sedimentary →

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Physical properties

Hardness: 5.5-6.5; Color: Metallic grey to black; Luster: Metallic to sub-metallic; Crystal structure: Trigonal; Specific gravity: 5.26

Formation & geological history

Formed by the precipitation of iron-rich groundwater through porous sandstone, often during the Jurassic period in the Navajo Sandstone of the American Southwest.

Uses & applications

Used as an ore of iron, in jewelry as beads/cabochons, and as a popular 'talisman' or grounding stone in spiritual circles.

Geological facts

These are often called 'Moqui Marbles' and are famous for their spherical or disc-like shapes. Similar structures have been discovered on Mars, known as 'Blueberries'.

Field identification & locations

Identified by their metallic grey appearance and high density. The most definitive test is a 'streak test'—rubbing it on unglazed porcelain will leave a characteristic rust-red streak.