Hematite has an extremely variable appearance. Its luster can range from earthy to submetallic to metallic. Its color ranges include red to brown and black to gray to silver. It occurs in many forms that include micaceous, massive, crystalline, botryoidal, fibrous, oolitic, and others.
Even though hematite has a highly variable appearance, it always produces a reddish streak. Students in introductory geology courses are usually surprised to see a silver-colored mineral produce a reddish streak. They quickly learn that the reddish streak is the most important clue for identifying hematite.
Hematite is not magnetic and should not respond to a common magnet. However, many specimens of hematite contain enough magnetite that they are attracted to a common magnet. This can lead to an incorrect assumption that the specimen is magnetite or the weakly magnetic pyrrhotite. The investigator must check other properties to make a proper identification.
If the investigator checks the streak, a reddish streak will rule out identification as magnetite or pyrrhotite. Instead, if the specimen is magnetic and has a reddish streak, it is most likely a combination of hematite and magnetite.
| Physical Properties of Hematite | |
| Chemical Classification | Oxide |
| Color | Black to steel-gray to silver; red to reddish brown to black |
| Streak | Red to reddish brown |
| Luster | Metallic, submetallic, earthy |
| Diaphaneity | Opaque |
| Cleavage | None |
| Mohs Hardness | 5 to 6.5 |
| Specific Gravity | 5.0 to 5.3 |
| Diagnostic Properties | Red streak, specific gravity |
| Chemical Composition | Fe2O3 |
| Crystal System | Trigonal |
| Uses | The most important ore of iron. Pigment, heavy media separation, radiation shielding, ballast, polishing compounds, a minor gemstone |