Hematite is a type of iron oxide, meaning that it contains closely packed oxygen molecules mixed with iron. It is the most abundant iron-containing mineral on Earth, and is an important source of iron. Various cosmetics and paints are made using this stone, and it also appears in jewelry and carvings in many parts of the world.
The mineral's color ranges from almost black to silvery gray to blood red. It forms in series of crystalline plates which build on each other, and often leaves a red streak if it is drawn across a surface. One of the most famous forms is the lustrous silvery gray, which is frequently used for ornamental purposes. In general, hematite contains about 70% iron ore and 30% oxygen.
A number of different terms are used to describe hematite, depending on color and composition. Hematite rose forms in a shape which resembles a flower. Tiger iron is layered with other minerals, such as quartz. Kidney ore takes a lumpy form which does indeed vaguely resemble a kidney. Specularite is highly flaky, and oolitic hematite takes the form of small grains of reddish brown material.
The name comes from the reddish color which emerges when hematite is powdered, and the reddish tint which many forms of the mineral have. The color reminded some observers of blood, and the Greek root hema, for blood, was used to describe the stone. Some early cultures believed that the mineral formed from the blood of soldiers killed on the battlefield. For this reason, the “bloodlike stone” was revered.
Other minerals are sometimes mixed in with hematite, as is the case with ilmenite, which also includes titanium. Ilmenite is more strongly magnetic, and it produces a white pigment when ground up. Hematite is also often found in combination with deposits of other rock, like corundum, another oxide mineral with a primary component of aluminum, rather than iron.
In addition to being used as a source of pigments and pure iron, hematite is also used in jewelry. The silvery gray form is most popular for this purpose, as it can be polished to a pure sheen. Pure hematite is often used to make simple rings and bracelets, and the stone is also turned into beads or set into other pieces of jewelry. Some stone carvers also work with the mineral to produce ornamental carved pieces.