Magnetite with Hematite
Magnetite (Iron II, III oxide) / Hematite (Iron III oxide) · Mineral Specimen and Opaque Iron Ore
Crystal System
Magnetite is Cubic (Isometric), often occurring as octahedral or dodecahedral crystals; Hematite is Trigonal (Hexagonal), often rhombohedral or platy.
Mineral Group
Oxides; Spinel Group (Magnetite) / Hematite Group (Hematite)
Chemical Formula
Magnetite: Fe3O4; Hematite: Fe2O3 (often found together as Lodestone or martite)
Formation Process
Primarily formed through Magmatic crystallization in igneous rocks, but also found in contact metamorphic deposits and hydrothermal veins.
About This Crystal
The specimen shows an opaque, metallic to sub-metallic luster with a heavy, granular texture. It features deep black to gunmetal gray grains characteristic of magnetite, interspersed with reddish-brown earthy zones typically associated with hematite or limonite oxidation.
Physical Characteristics
Color: Black/Dark Gray with red-brown areas. Streak: Black (Magnetite) / Cherry Red to Brown (Hematite). Cleavage: None (Magnetite has octahedral parting). Fracture: Conchoidal to uneven. Specific Gravity: 5.15 - 5.2. Strongly Magnetic.
Optical Properties
Opaque; metallic luster. In thin sections, it shows internal reflections that are reddish-brown for hematite; magnetite remains black.
Hardness & Durability
Origin Region
Globally distributed; notable deposits in Sweden (Kiruna), USA (Michigan/Minnesota), Brazil (Minas Gerais), and Western Australia.
Hardness & Durability
Mohs hardness 5.5 - 6.5. Relatively brittle. Stable in most conditions but can prone to further oxidation if exposed to acidic environments.
Care & Maintenance
Clean with a dry, soft brush or slightly damp cloth. Avoid harsh chemicals and ultrasonic cleaners. Store in a dry environment to prevent rusting of the iron content.
Rarity & Value
Common. High economic value as iron ore, but low to moderate value as a collector specimen unless featuring well-defined octahedral crystals. Rarely treated.
Special Characteristics
Strongly ferrimagnetic property (Magnetite) is the most notable feature. Samples that act as natural magnets are called Lodestone.
Lore & History
Historically used in the first compasses (Lodestone) by ancient mariners and Chinese diviners. It is traditionally associated with grounding, protection, and 'attracting' goals or manifestations in folk medicine and modern crystal lore.