Magnetite is a widespread iron oxide mineral easily identified by its strong magnetic properties. It typically occurs as well-defined octahedral crystals or massive aggregates in igneous and metamorphic environments, and is a primary ore of iron.
Spotting magnetite in the field
Field marks- 1
Strongly magnetic, enough to pick up paperclips in the lodestone variety
- 2
Black, metallic to submetallic, forming octahedral crystals
- 3
Leaves a black streak, hardness 5.5 to 6.5
Carry a magnet and this identifies itself. Magnetite makes up most of the black sand in any placer concentrate, which is why gold panners know it well: it is the heavy black material you separate out to find the gold underneath. Lodestone is the naturally magnetized variety that acts as a permanent magnet. It forms octahedra, eight triangular faces, which is a useful shape cue in outcrop.
Straight answers
- Is it worth cutting?
- Not cut. A specimen and indicator mineral.
- What is it really worth?
- Effectively none. Lodestone that visibly picks up iron filings has novelty value.
- Can you legally keep it?
- Ordinary personal-use collecting rules apply.
Often confused with
Magnetite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak. Magnetite is black, hematite is red-brown. Magnetism also separates them.
How to tell apart: The most common meteorwrong of all. Magnetite is magnetic and heavy like a meteorite, but it streaks black and often forms octahedral crystals, which meteorites never do.
Often found alongside magnetite
Minerals reported to co-occur with magnetite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃O₄
- Mohs hardness
- 5.5-6.5
- Density
- 5.1-5.2 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Octahedral Crystals, Massive, Granular
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Industrial, Ore Mineral
- Host rock
- Igneous, Metamorphic, And Sedimentary Rocks
- Typical price
- $5-50 for small specimens, higher for large, well-formed crystals
Where rockhounds find magnetite
71 mapped spotsClassic worldwide localities
- Kiruna, Sweden
- Magnet Cove, Arkansas, USA
- Cerro de Mercado, Mexico
- Kola Peninsula, Russia
U.S. states with magnetite
Each link opens a state-specific list of mapped rockhounding spots that produce magnetite.
Field-hunting tip
Look in igneous, metamorphic, and sedimentary rocks country, the host setting where magnetite typically forms. If you start seeing quartz, pyrite, chalcopyrite in float, you are in the right ground. Field specimens usually show a octahedral crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, North Carolina, Pennsylvania. Start trip planning there.
Common questions
How do you identify magnetite?+
Where is magnetite found?+
Can I find magnetite in the United States?+
How much is magnetite worth?+
What rocks look like magnetite?+
What minerals are found with magnetite?+
What kind of rock does magnetite form in?+
What is magnetite used for?+
Find magnetite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
