mineral

Magnetite-rich ironstone

Magnetite, Fe₃O₄, likely in a dense ironstone matrix

AI-generated identification · may be incorrect

Black to brown-black, metallic to submetallic luster, opaque, granular or massive texture; Mohs hardness 5.5–6.5, specific gravity about 5.2. It should strongly attract a magnet; the surface appears naturally weathered rather than crystalline.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms in igneous, metamorphic, and sedimentary iron-rich environments, including banded iron formations and hydrothermal deposits. The specimen’s exact age and locality cannot be determined from the image alone.

Uses & applications

Used as an iron ore, dense aggregate, pigment, and sometimes as a collectible magnetic mineral specimen; it has little jewelry value unless attractively polished.

Geological facts

Magnetite is one of the most strongly magnetic common minerals and can produce naturally magnetized lodestone. Brown surfaces may represent oxidation to hematite or limonite.

Field identification & locations

Test with a strong magnet, streak it on unglazed porcelain (black streak), and compare its high density with ordinary dark rocks. Common sources include Australia, Brazil, Sweden, South Africa, and the United States.