Hematite
Iron Oxide var. Specularite · Mineral Specimen / Industrial Mineral
Crystal System
Trigonal; massive and rhombohedral crystals, often appearing granular or micaceous as specularite.
Mineral Group
Oxides (Hematite group)
Chemical Formula
Fe2O3
Formation Process
Primarily sedimentary through precipitation from water, but also results from hydrothermal veins and volcanic fumaroles (igneous).
About This Crystal
An opaque, dark gray to black mineral with a distinctive metallic to sub-metallic luster. This specimen exhibits a granular 'specular' appearance, characterized by tiny glittering flakes that reflect light.
Physical Characteristics
Color: Steel-gray to black with reddish tints. Streak: Characteristic cherry-red to brownish-red. Fracture: Uneven to sub-conchoidal. Specific Gravity: 5.26. Fluorescence: None.
Optical Properties
Opaque; extremely high refractive index (2.94-3.22) but not measurable by standard refractometry. Weakly pleochroic in thin sections.
Hardness & Durability
Origin Region
Notable sources include Brazil (Minas Gerais), USA (Lake Superior region), Morocco, and Australia. Forms in iron-rich sedimentary and igneous environments.
Hardness & Durability
Mohs hardness: 5.5 - 6.5. Toughness: Brittle. Generally stable but can be scratched by quartz or steel.
Care & Maintenance
Avoid acidic cleaners. Clean with warm soapy water and a soft brush. Dry thoroughly to prevent surface oxidation over long periods. Store away from harder stones.
Rarity & Value
Common. Value is generally low for industrial/massive specimens, though fine specular or 'iron rose' crystals are prized by collectors.
Special Characteristics
Specularite variety exhibits 'sparkle' due to mirror-like mica-like flakes. It is the primary ore of iron. Occasionally slightly magnetic if containing magnetite inclusions.
Lore & History
Used since prehistoric times as a pigment (ochre). Known as the 'Stone for the Mind' in traditional lore, believed to aid grounding and protection. Historically used by Roman soldiers for protection.