Magnetite in Matrix
Magnetite (IMA-approved mineral species) · Industrial Mineral and Mineral Specimen
Crystal System
Cubic (Isometric); typically occurs as octahedral crystals, though this specimen shows a massive, granular, and disseminated habit.
Mineral Group
Oxides (Spinel group)
Chemical Formula
Fe2+Fe3+2O4 (Iron(II,III) oxide)
Formation Process
Igneous and Metamorphic; forms as a primary mineral in igneous rocks like basalt and gabbro through magmatic segregation, or in contact metamorphic deposits (skarns) and hydrothermal veins.
About This Crystal
The specimen features black, semi-metallic to dull grains embedded in a lighter, tan-to-grey rocky matrix. The magnetite appears as opaque, irregular clusters with a granular texture and occasional micro-crystalline facets that reflect light.
Physical Characteristics
Color: Black to brownish-black; Streak: Black; Luster: Metallic to sub-metallic; Fracture: Uneven to sub-conchoidal; Specific Gravity: 5.17–5.18; Magnetism: Strongly magnetic (most magnetic mineral on Earth).
Optical Properties
Opaque; Single refraction (Isometric); No pleochroism or birefringence visible; Metallic reflectance is common in polished or fresh surfaces.
Hardness & Durability
Origin Region
Common worldwide; notable sources include Kiruna (Sweden), Adirondack Mountains (USA), and various localities in Western Australia. Often found in banded iron formations or igneous intrusions.
Hardness & Durability
Mohs hardness: 5.5 to 6.5; Toughness: Brittle; Stable under normal atmospheric conditions but prone to oxidation (rusting) if exposed to moisture over long periods.
Care & Maintenance
Clean with a dry brush or damp cloth; avoid prolonged immersion in water to prevent oxidation. Keep away from strong magnets and sensitive electronic equipment due to its inherent magnetic field.
Rarity & Value
Common; very affordable as raw mineral specimens. Value is primarily in the industrial extraction of iron or for educational collectors. Well-formed octahedral crystals are more valuable than this granular form.
Special Characteristics
Strongly magnetic; some varieties (lodestone) act as natural magnets that can attract iron filings. Exhibits ferrimagnetism.
Lore & History
Historically used as lodestones to create the first magnetic compasses (sailing technology). Symbolically associated with grounding, protection, and 'attraction' in traditional lore. Historically significant in the development of the steel industry.