Hematite, chemically identified as iron(III) oxide (Fe2O3), is a mineral whose scientific properties underpin its vast industrial importance. Its composition, structure, and physical characteristics make it indispensable for everything from steel production to advanced technological applications. A thorough understanding of these scientific aspects is crucial for appreciating its value.

The chemical composition of hematite is primarily iron and oxygen, with a theoretical formula of Fe2O3, making it rich in iron content (around 70% by weight). This composition dictates many of its properties. Hematite crystallizes in the trigonal system, often forming tabular or rhombohedral crystals, though it's commonly found in massive, botryoidal, or earthy forms. Its hematite mineral properties such as hardness range from 5.5 to 6.5 on the Mohs scale, classifying it as moderately hard but brittle. This contrasts with its metallic or earthy luster, which can vary significantly depending on the specific variety.

A key identification feature of hematite is its streak – a reddish-brown powder left when the mineral is scratched on an unglazed porcelain plate. This property remains consistent across different hematite appearances, making the hematite streak test a reliable diagnostic tool. While pure hematite is only weakly magnetic, many natural specimens contain enough magnetite to exhibit some magnetic attraction. This characteristic can sometimes be confused with magnetite itself, emphasizing the need to check other properties like the streak.

The industrial importance of hematite is multifaceted. As the world's primary source of iron ore, it is the foundation of the steel industry, essential for construction, manufacturing, and transportation. Beyond metallurgy, hematite's high density makes it useful for radiation shielding and as ballast. Its fine powder serves as a pigment in paints and cosmetics, and its unique metallic luster makes it popular for jewelry. The ongoing scientific research into hematite's properties continues to uncover new applications, further solidifying its critical role in science and industry.