Magnetite
Magnetite · Mineral Specimen and Opaque Gemstone; primary iron ore
Crystal System
Cubic (Isometric); habit is typically octahedral, dodecahedral, or massive/granular (as seen in this specimen)
Mineral Group
Oxides (Spinel group)
Chemical Formula
Fe3O4 (Iron Oxide)
Formation Process
Primarily magmatic (late-stage crystallization) or hydrothermal; also forms through contact metamorphism and in banded iron formations.
About This Crystal
An opaque, iron-black to dark grey mineral with a submetallic to metallic luster. This specimen shows a massive, granular texture with a finely crystalline surface that glitters under direct light.
Physical Characteristics
Color: Iron-black to dark grey; Streak: Black; Fracture: Uneven to subconchoidal; Specific Gravity: 5.1-5.2; Strongly magnetic; Brittle tenacity.
Optical Properties
Opaque; refractive index is not applicable. Shows metallic to submetallic luster; non-pleochroic. Under reflected light, it appears greyish-white.
Hardness & Durability
Origin Region
Globally distributed; notable sources include Kiruna (Sweden), South Africa, USA (Utah/New York), and Brazil. Found in igneous and metamorphic rocks.
Hardness & Durability
Mohs hardness: 5.5 to 6.5. Good durability but susceptible to oxidation and should be kept dry to prevent rusting.
Care & Maintenance
Avoid acidic chemicals and prolonged exposure to moisture (to prevent rust). Clean with a dry or slightly damp cloth; avoid ultrasonic cleaners if fractured.
Rarity & Value
Common mineral; generally inexpensive as small specimens. Value increases for well-formed octahedral crystals or 'lodestone' varieties with natural polarity.
Special Characteristics
Ferrimagnetism (strongly attracted to magnets). Some specimens act as natural magnets called Lodestones. High iron content makes it noticeably heavy.
Lore & History
Historically used as the first natural compass (lodestone) by ancient mariners. In lore, it is believed to be a 'grounding' stone that aligns energy and attracts abundance.