Fe₃O₄

These samples of magnetite are displayed in the Smithsonian Museum of Natural History. Magnetite is an oxide mineral of iron and has the composition Fe₃O₄. This crystal shows the characteristic geometry. The sample is from Binnatal, Valais, Switzerland. The sample width is about 8 cm with the crystal dimension being about 2 cm.

Magnetite and hematite are the two major ores for iron. Magnetite is associated with the term "lodestone", which refers to a variety of magnetite that holds a magnetic field.

This interesting sample from Stubach Tal, Todtenkopge, Salzburg, Austria shows magnetite with apatite and tremolite. The overall sample size is about 20x25 cm with the magnetite crystals being on the order of a 3-4 centimeters.

This large crystal of magnetite measures about 6x7 cm! It comes from Minas Gerais, Brazil, the origin of so many extraordinary large crystals.

This magnetite sample is from Tilly Foster mine, Brewster, New York. It is about 15 cm across.