Hematite is easily identifiable by its characteristics.
Hematite can have important uses in society, including its role in the production of iron, which may make it an interesting mineral for geology enthusiasts to identify. The rock was the source of about 90 percent of the iron mined in the United States in 2002 and is also used to make jewelry. Its often unusual shape and density has led some people to mistake it for a meteorite. Hematite has several characteristics by which it can be identified.
1. Look at the rock. If it is a black or rusty color it could be hematite, which can be found in both dark and reddish hues. Specular hematite may have a dark and reflective appearance with a metallic luster, while oolitic hematite has a brick-red coloring and contains tiny visible spheres.
2. Pick up the rock. If the rock seems heavy for its size, it may be hematite. The mineral has a specific gravity — a measure of its density in relation to that of water — of 5.25.
3. Rub the rock against the porcelain streak plate. If it leaves a reddish-brown streak, it may be hematite.
4. Scratch the surface of the rock with your fingernail. If you are not able to make a mark this way, use the copper penny, then the glass plate or steel knife, then the steel file. This is called the Mohs Hardness Test, and hematite is normally a five or six on the scale. This means that it may be scratched by the glass plate, steel knife or steel file, but the copper penny and fingernail would not make a mark.