HEMATITE belongs to the group of oxide minerals. In general, it is found in compact masses, and its surface can have a shiny or earthy appearance, depending on the material around it. HEMATITE has a peculiar metallic luster. Its crystals are often tabular or hexagonal. HEMATITE is a relatively hard mineral, however, although it cannot be scratched with the blade of a knife, collectors need to be very careful not to bump it, as it is not strong enough to withstand this type of damage.Hematite is the main source of industrial iron in the world. It is the most widespread of all iron-containing minerals. In contact with air, hematite turns red, but when extracted it is dark gray like iron. Although it is not a mineral with the highest concentration of iron (that title belongs to magnetite), it is the most abundant and therefore the main source of industrial iron. Hematite is a primary and secondary mineral. When it occurs as a primary mineral, that is, that has not undergone any alteration, it appears mainly as an accessory mineral in igneous rocks and hydrothermal veins, and in sedimentary rocks. It occurs as a secondary mineral when there is precipitation of water that contains iron; in this case, hematite replaces older minerals. Some of the finest samples are used to make ornaments and gemstones, but care must be taken not to scratch them, as they register only 6.5 on the Mohs hardness scale.