Gemologists use several classifications to determine the structure and appearance of gemstones. These technical terms are indicated in visual inspections:

Luster - which is the shine or glow of reflected light from a gemstone's surface.
Transparency - which allows light to go through or opaque (not able to see through); adamantine (like diamond); vitreous (like glass), silky, and resinous (like amber resin); greasy (or waxy) and metallic (of which its shine is similar to polished metal).

Very few gems have the metallic luster as hematite which is an iron-oxide mineral. Hematite is opaque and has an extremely variable appearance. Its luster can range from earthy to submetallic to metallic. Its color ranges from red to brown and black to gray to silver. Hematite is harder than pure iron but is much more brittle. They have a hardness of 5.0 to 6.0 on the Mohs scale.

Hematite forms in the shape of crystals and has the same crystal structure as sapphires and rubies.

Hematite comes from the Greek HAIMATITES LITHOS which means "blood-red stone." This is because they all leave a rust-red streak when scratched in a white ceramic plate. This red streak is an important clue in identifying hematites.

Hematites were often used as red pigmentation in ancient times.

Varieties of hematite include: kidney ore (looks like a kidney), martite, iron rose and specularite (specular hematite). Maghemite (a product of oxidised magnetite) is also loosely called a hematite.

Many specimens of hematite contain enough magnetite that they are attracted to a common magnet. Magnetite is attracted to a magnet and can be magnetized to become a permanent magnet itself. Very important to note is that a magnetite leaves a black streak unlike the red streak from hematites.

Magnetite reacts with oxygen to produce hematite. If a specimen is magnetic and has a reddish streak, it is most likely a combination of hematite and magnetite.

Hematites had been used as a red pigment in pictographs over 40,0000 years ago and were used by the ancient Greeks, the Babylonians, Egyptians and the Romans.

In ancient Rome, hematite was the material used for signet rings and intaglios. In England, during the Victorian era, hematite was used in jewelry. Many Native American tribes used red ochre, the powdered form of hematite, extensively as a face paint for religious and war-related ceremonies. Note: Red ochre contains unhydrated hematite, whereas yellow ochre contains hydrated hematite.

Ancient Egyptians placed hematite amulets, representing pillows, in tombs to help mummies arise and move on to the afterlife. See, for example, Chapter CLXVI: The Chapter of the pillow in THE BOOK OF THE DEAD, The Papyrus of Ani. [Note, CLXVI = 166].

Ancient Romans associated hematite to Mars, the god of war whom they glorified. Their warriors rubbed their body with the powdered hematite as it was believed it made them invincible.

Healers of the Middle-Ages recommended hematite for headaches and inflamed eyes. For example, a mixture of honey and powdered hematite was prescribed as a salve to be applied on the troubled eye. Another treatment method was to take a hematite stone and rub it very gently over the eye lids.

Both hematite and bloodstone were known and used in ancient Babylon and Assyria. It was believed that the source of hematite was from the blood of dragons and that it had the power to stop bleeding and to cure any mental ailment.

Varieties of hematite have been used since ancient times to cure burns and for stomach troubles such as infections of the bladder, for the healing of wounds, and against the venom of serpents.

Hematite was also recommended for use against venereal diseases or the diseases of Venus. Mars used to battle Venus in medical astrology.

Hematite has been found on planet Mars. Because terrestrial hematite is typically a mineral formed in watery environments, this discovery points to the fact that there was once water on Mars. An abundance of hematite in Martian rocks and surface materials gives the landscape a reddish-brown color and that is why the planet appears red in the night sky.

Rich deposits of hematite have been found in the UK (Cumberland), Brazil, China, Bangladesh, New Zealand, the Czech Republic and Minnesota, the United States. Hematite is also found in the mineral hot springs of Yellowstone National Park in North America. The island of Elba has been a source of hematite since the time of the Etruscans.