Hematite, a mineral that has the ability to change its form, traces its roots back to the Stone Age.

As the primary source of iron ores on Earth, hematite has been instrumental in shaping civilizations for millennia. Initially, it served as the dominant pigment in cave paintings, often carrying a reddish tone — a hallmark of hematite.

Hematite, which remains the key source of iron, transitioned the world from the Stone Age into the Iron Age. The mineral’s red streak earned it the nickname 'bloodstone,' and its name is derived from the Greek word for blood, 'haima.'

The stone can appear in shades of silver-gray, black, brown, or red, and may shine as metallic crystals or appear dull like a rough reddish rock. Hematite also holds significance beyond Earth. It’s the reason Mars has its red hue, as roughly 10-15 percent of the Martian soil is composed of this mineral.

What Is Hematite?

Hematite is an iron oxide, consisting of 70 percent iron and 30 percent oxygen, with the chemical formula Fe₂O₃. As one of the Earth's most abundant minerals, it is ideal for mining to extract iron and iron-based products such as steel.

Although hematite is abundant, it is rarely found in isolation on Earth; it is more commonly found mixed with other minerals, such as magnetite.

Hematite forms through the reaction of hot magmas with surrounding materials, likely eroding into concentrated layers within sedimentary beds, where gravity distribution separates them. It can also precipitate from lake waters, creating layers at the bottoms of lakes,” explains Brad LeBlanc, senior geoscientist for Sweet Lake Land & Oil, in an email interview.

Since hematite can form in various ways, it can exhibit different physical characteristics. This makes it somewhat challenging to identify based on appearance alone, especially for those studying geology.

It may seem counterintuitive, but a rainbow-colored metallic crystal and a rough black specimen are actually the same type of mineral — both are forms of hematite.

The Bloodstone

Hematite has a distinct feature that gives away its identity, tied to its nickname 'bloodstone.' Despite its various appearances, when scraped, the mineral always leaves behind a reddish powder due to its high iron and oxygen content.

"If you're unsure about what specimen you're holding, you can test it by scraping it on something. If the streak is reddish or reddish-brown, it's most likely hematite," advises LeBlanc.

How Hematite Was Formed

Around 2.4 billion years ago, when Earth was entirely submerged in primordial oceans, iron was plentiful in the waters. As early plants evolved that could process sunlight and photosynthesize, the ocean's oxygen content began to rise.

This oxygen reacted with the iron in the ocean, creating rust particles. Over time, these particles settled to the ocean floor, forming banded iron ore deposits, which have become the primary source of hematite we see today. This process continued for hundreds of millions of years.

In addition to hematite, these sedimentary iron deposits also contain magnetite, another significant iron source with the chemical formula Fe₃O₄. The varying mix of these minerals in different proportions is one of the factors that leads hematite to appear in different forms.

Uses for Hematite

Though hematite is predominantly mined for its iron content, much like other iron ores, it has had a variety of uses dating back to ancient civilizations.

Hematite is a key component of 'red ochre,' a pigment widely used in prehistoric cave art, cosmetics, glazes, and early paintings. Since rust and rust-based minerals naturally take on a red hue, early cultures had easy access to this color. Red ochre even found its way into Renaissance paintings.

Hematite also takes on metallic and crystalline forms, which makes it a popular choice for jewelry. When polished or tumbled, the mineral shines with a smooth metallic finish, making it ideal for creating beads in various shapes and sizes.

The mineral has been regarded as a 'healing stone,' believed to alleviate conditions such as anemia, leg cramps, and insomnia. However, there is no scientific evidence to support these claims.

On a more scientific note, hematite has a legitimate medical application: It can block X-rays, making it an essential material for radiation shielding in medical devices.

Despite these alternative uses, the majority of hematite's demand is for iron production, with these secondary applications being a relatively small part of its overall use.

Although hematite can be found all around the globe, substantial quantities are extracted in regions like China, Brazil, Venezuela, Australia, and South Africa, as well as throughout the U.S. and Canada. Some of these mines extract over 100 million tons of iron ore (including hematite, magnetite, and other materials) annually.