The chemical composition of hematite is Fe2O3, and its crystal belongs to the oxide mineral of tripartite system.

The western name comes from the Greek word "blood", which means that this mineral is often red.

It is an oxide of iron and the main mineral of iron. Although other metals have gradually replaced iron, iron is still the most important metal.

Therefore, hematite is one of the most important minerals in economy. There are only a few places where hematite has perfect metallic sparkling diamond crystals. But more often, the crystal is flat and even forms a thin plate. Some samples are plate-shaped and clustered into roses, which are called iron roses. Sometimes it is a scaly aggregate called specularite. These well-crystallized hematite varieties are all black, but the stripes, that is, the color of mineral powder, are all black. The so-called kidney-shaped iron ore is this red color. Kidney-shaped iron ores are some radial aggregates with kidney-shaped surfaces. Red is the color of most soil hematite without crystal form. Ochre is this kind of laterite hematite, which was once used as a pigment.

Hematite is an accessory mineral widely distributed in various rocks. It appears in many igneous rocks in the form of fine particles, and forms huge blocks in regional metamorphic rocks under special circumstances.

In red sandstone, hematite is the cement of timely particles, which dyes rocks. If it has economic value, it must contain tens of millions of tons of hematite, which is caused by large-scale deposition. There are many such iron ores in Precambrian strata, which usually contain silicon impurities.

Iron-rich ore with iron content of at least 50% is enriched by leaching silicon dioxide from rainwater. These rich ores are the source of iron in the world, but their reserves are decreasing day by day. In order to make up for this deficiency, mining companies are turning their attention to the original iron-containing buildings, the so-called iron-containing quartzite. This kind of rock contains only 25-30% iron, but its reserves are huge. By mechanical means, it can be used to make.

Large-scale hematite deposits have been discovered and mined on all continents. 196 1 year, the Soviet Union replaced the United States as the largest producer, followed by France, Canada, China, Sweden and Australia. In the United States, since the end of 19, the largest mineral source is Precambrian rocks in the Great Lakes region.