Magnetite

Fe2+Fe23+O4 - Mohs Hardness: 5 1/2 - 6 1/2.    Magnetite is an important ore of iron, the main ingredient of steel.  Pure iron being quite soft is most commonly combined with alloying elements to make steel, carbon being the most important.  It is the most magnetic of all naturally occurring minerals on Earth.  Naturally magnetized pieces called lodestone will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism.  Huge deposits have been found in banded iron formations.
Abstract/Description: Fe2+Fe23+O4 - Mohs Hardness: 5 1/2 - 6 1/2. Magnetite is an important ore of iron, the main ingredient of steel. Pure iron being quite soft is most commonly combined with alloying elements to make steel, carbon being the most important. It is the most magnetic of all naturally occurring minerals on Earth. Naturally magnetized pieces called lodestone will attract small pieces of iron, which is how ancient peoples first discovered the property of magnetism. Huge deposits have been found in banded iron formations.
Subject(s): Keweenaw Peninsula, Northern Michigan, United States
environmental sciences