Hematite: Properties, Facts and Photos

Hematite is an important iron oxide mineral that has been used by humans for thousands of years. This article looks at what it is, its meaning, properties, and where it's found.

What is Hematite?

Hematite (also spelt 'haematite') is a major source of iron and one of the main forms of iron oxide, with the other being magnetite. 

Hematite is 70% iron, 30% oxygen by weight. Its chemical composition is two iron atoms and three oxygen atoms.  

Hematite, which often occurs with other iron minerals such as goethite and magnetite, is abundant worldwide. Vast amounts are found in a type of rock called a banded iron formation.  

Hematite is widely used in the steel industry as an important ore of iron.

Due to its high density, hematite feels unusually heavy for its size. Although much harder than pure iron, it's also brittle. On the Mohs scale of hardness, it grades 5.5 to 6.5.

Its colour ranges from black to silver grey, brown to reddish-brown and can also be red. Well-formed hematite crystals are rare.When used as a gemstone, it tends to be cut as a cabochon. Small faceted stones, although rare, can resemble black diamonds.

Hematite has a blood-red to reddish-brown streak. Streak describes the colour of a mineral in powdered form.

When heated, hematite can partially convert into magnetite, a naturally magnetic iron oxide, which is why heated hematite can sometimes show weak magnetic properties.

Coarse-grained grey hematite has been identified on Mars, particularly in a region called Meridiani Planum. Unlike the fine red hematite dust that gives Mars its colour, this grey, crystalline form is linked to the presence of liquid water.

These deposits were first detected from orbit in the late 1990s and later examined up close by NASA’s Opportunity rover, which found small spherical concretions rich in grey hematite scattered across the surface. These are similar to nodules that form in sedimentary environments on Earth, such as lakes, groundwater systems, or hydrothermal settings.

For this reason, their presence on Mars suggests that liquid water once existed there, billions of years ago.

The Meaning of Hematite

The meaning of hematite originates from the Greek word 'haema', which means 'blood'. This is because of its red-coloured streak.

Throughout history, this meaning has led to hematite's widespread use for blood disorders. Stones have also been worn to protect the wearer from bleeding.

The prefix 'haema' is present in the word 'haemoglobin', which is the protein that carries oxygen around the blood. It's also the prefix in 'haematoma', a solid swelling of clotted blood, and 'haematology', which is the study and treatment of the blood.

The ancient Greek philosopher Theophrastus describes 'haematites' as having the colour of 'dried blood'. The Roman author and naturalist Pliny the Elder also refers to haematite and says its colour is 'blood red'.

Pliny also talks about a 'precious stone' called 'haematites', but historians believe it's likely to be red jasper.

Main Component of Red Ochre

Red ochre, one of the oldest pigments on the planet, is made up primarily of hematite. It has been identified in cave paintings known to be at least 40,000 years old. Red ochre is believed to be one of the earliest powders that originates from a natural mineral.

Traces of hematite have been found on skeletal remains dating back around 12,000 years, indicating the use of red ochre in Neolithic burial practices. More recently, it has been widely used by Native American Indians. Hematite was also popular during the New Age movement of the 1970s and 80s.

Today, it's still widely used as a pigment, and many red colours come from iron oxides, including hematite.

Article Pictures

The hematite in the first photo is on display in the Smithsonian National Museum of Natural History, Washington, D.C.

The second photo is courtesy of Arturo R Montesinos.

The hematite in the third photo is courtesy of Stan Celestian. 

The piece in the last photo is housed in the Harvard Museum of Natural History, Massachusetts.

Photos 1 and 4: Stone Mania.

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Magnetite (in granitic matrix): Courtesy of Stan Celestian. Red Jasper: Courtesy of James St. John.