mineral

Magnetite (potentially Hematite-rich)

Magnetite (Fe3O4)

Hardness: 5.5-6.5; Color: Iron-black to dark grey; Luster: Metallic to sub-metallic; Crystal structure: Isometric (octahedral); Cleavage: None (parting sometimes present); Specific gravity: 5.1-5.2

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

Identified February 17, 2026More mineral →

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Physical properties

Hardness: 5.5-6.5; Color: Iron-black to dark grey; Luster: Metallic to sub-metallic; Crystal structure: Isometric (octahedral); Cleavage: None (parting sometimes present); Specific gravity: 5.1-5.2

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments. Often found in banded iron formations (geological age: 2.4 - 1.8 billion years) or as a magmatic segregation in mafic igneous rocks.

Uses & applications

Primary ore of iron for steel manufacturing; used in industrial catalysts, pigments, and as a polishing abrasive. High-quality specimens are collected for mineral study.

Geological facts

Magnetite is the most magnetic naturally occurring mineral on Earth. Naturally magnetized pieces called lodestones were used to create the first magnetic compasses.

Field identification & locations

Identify in the field using a strong magnet; the specimen should be strongly attracted. Look for a black streak when rubbed on a porcelain plate. Found globally, notably in Sweden, Brazil, and the USA (Mesabi Range).

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

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metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral