Hematite Nodules (Moqui Marbles style)

Physical Properties

Hardness: 5.5-6.5; Color: metallic grey to black with reddish-brown streak; Luster: Metallic to earthy; Crystal Structure: Hexagonal; Specific Gravity: 5.26

Formation & Geological History

Formed by the precipitation of iron-rich minerals from groundwater flowing through permeable sedimentary rock, typically sandstone, often during the Jurassic period.

Uses & Applications

Primary ore of iron, used in pigments (ochre), jewelry (beads), and as a popular specimen for mineral collectors.

Geological Facts

Small rounded hematite or goethite concretions found in sandstone are often called 'blueberries' on Mars, providing evidence of past water presence on the red planet.

Field Identification & Locations

Identified by their distinctive round or botryoidal shape and heavy weight for their size; a streak test on unglazed porcelain will leave a characteristic rust-red mark.

Identified on: 5/1/2026

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