About
Magnetite may form a yellow-brown rust coating if washed or kept in a moist area. If a specimen is washed, it should be dried to prevent rusting. Rust can easily be removed by soaking the Magnetite in a rust-removing solvent such as Iron Out.
The mineral Hematite is known to form pseudomorphs over Magnetite. Such pseudomorphs are commonly known as Martite, and their appearance may be very similar to regular Magnetite. However, they differ from Magnetite in that they are only weakly attracted to magnetic fields, and have a reddish-brown streak.
Crystal Forms & Aggregates
Other ID Marks
Striking Features
Environment
Varieties
✓ common · ✗ uncommon
- Lodestone— Massive, magnetic variety of Magnetite that acts as a natural magnet.
- Martite— Hematite pseudomorph after Magnetite.
- Chrome-magnetite— Chromiumrich variety of Magnetite.
- Taconite— Banded formation known as taconite - the primary Iron ore known primarily from the Mesabi Range in Minnesota composed of dark, metallic-lustered layers of Magnetite combined red chert in between.
- Titano-magnetite— Titanium-rich variety of Magnetite.
Uses
Noteworthy Localities
Single octahedral Magnetite crystals, often in matrix, are well known from Binn Tal, Wallis, Switzerland. These crystals sometimes have characteristic layer growths or triangular striations. Some of the largest Magnetite deposits exist in northern Sweden, with very good crystals having come from Nordmark. Well-formed crystals come from the Kovdor Mine in the Kola Peninsula, Russia; and heavily striated crystals with growth layers come from Parachinar, Pakistan. In South America, highly lustrous and perfectly formed octahedral Magnetite crystals are mined at Cerro Huanaquino, Potosi, Bolivia.
In the U.S., large Magnetite masses, sometimes with partial or full octahedral faces, have come from Franklin and Ogdensburg, Sussex Co., New Jersey; and perfect octahedral crystals from Chester, Windsor Co., Vermont. Lustrous cubic crystals were found in Balmat, St. Lawrence Co., New York, producing a unique habit of Magnetite unlike any other. The French Creek Mine, St. Peters, Chester Co., Pennsylvania has produced some large octahedrons. The magnetic variety Lodestone comes from the Iron Springs area (Dixie National Forest,) Washington/Iron counties, Utah; and from Magnet Cove, Hot Spring Co., Arkansas.
There are several classic Magnetite localities on the East Coast of the United States, which have been out of production for many decades or even centuries. Unique dodecahedral crystals, often with rounded corners, were at one time mined at the old Tilly Foster Mine, Brewster, Putnam Co., New York. Massive and poorly crystallized Magnetite was once mined in abundance in the 19th-century iron mines in the Ramapo Mountains, Sterling Forest, and Hudson Highlands region of Orange/Rockland Counties, New York., as well as the Jersey Highlands of Passaic Co., New Jersey. Laurel Hill (Snake Hill) in Secaucus, Hudson Co., New Jersey has produced excellent, isolated octahedral crystals in a diabase matrix.
Common Mineral Associations
Distinguishing Similar Minerals
Spinel - Not attracted to magnetic fields, has a white streak.
Ilmenite - Lighter streak.
Chromite - Has a brownish streak.Hematite pseudomorph after Magnetite - Has a weaker magnetic attraction.
Photos
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