Ilmenite Identification Guide
A field guide to identifying ilmenite, the iron-titanium oxide, using its black streak, weak magnetism, and metallic luster.
Read the full Ilmenite encyclopedia entry →
What Ilmenite Looks Like
Ilmenite is iron titanium oxide (FeTiO3), the main ore of titanium. It is a common, dark, heavy accessory mineral:
- Color: iron-black to brownish-black
- Luster: metallic to submetallic
- Transparency: opaque
- Habit: thick tabular or platy crystals, also massive, granular, and as rounded grains in black sands
Step-by-Step Field ID Checklist
- Note the metallic black appearance and significant heft.
- Test the streak. Rub on unglazed porcelain — ilmenite gives a black to brownish-red streak (see below).
- Test magnetism. It is weakly magnetic; a strong magnet attracts it but far less strongly than magnetite.
- Check hardness. Mohs 5–6; harder than your fingernail and a copper coin, about knife-hardness.
- Look for no cleavage and conchoidal to uneven fracture.
- Consider the setting — mafic igneous rocks and heavy-mineral beach/river sands.
Key Diagnostic Tests
- Streak: black to brownish-red — the brownish tint distinguishes it from magnetite (black streak) and hematite (cherry-red streak).
- Magnetism: weakly magnetic; sometimes only after heating. Much weaker than magnetite.
- Hardness: 5–6.
- Cleavage: none; parting may be present.
- Density: high, ~4.7 g/cm3, so it feels heavy.
- No acid reaction.
Common Look-Alikes
- Magnetite: strongly magnetic (sticks firmly to a magnet) with a pure black streak; ilmenite is only weakly magnetic with a browner streak.
- Hematite: gives a distinctive cherry-red to red-brown streak and can be earthy or micaceous; ilmenite's streak is darker.
- Chromite: brown streak, weakly or non-magnetic, but associated with ultramafic rocks; very similar — density and setting help.
- Rutile: brown-red, adamantine luster, harder (6–6.5), pale brown streak.
- Columbite/tantalite: heavier still and tied to granitic pegmatites.
Where It Is Found
Ilmenite is widespread in mafic and ultramafic igneous rocks (gabbro, anorthosite, layered intrusions), in some metamorphic rocks, and concentrated in heavy-mineral beach and river sands ("black sands"). Major sources include Norway, Canada, South Africa, Australia, India, and the United States.
Frequently asked questions
How can you tell if it's real ilmenite?
Look for a heavy, metallic iron-black mineral with a hardness of 5–6, no cleavage, weak magnetism, and a black to brownish-red streak. The browner streak and weaker magnetism separate it from magnetite and hematite.
Is ilmenite magnetic?
It is weakly magnetic — a strong magnet attracts it, but much less forcefully than magnetite, which clings firmly. Some ilmenite becomes more magnetic after heating.
What is the difference between ilmenite and magnetite?
Magnetite is strongly magnetic with a pure black streak, while ilmenite is only weakly magnetic and gives a black to brownish-red streak. Ilmenite is also a titanium ore, whereas magnetite is iron oxide.
What does ilmenite look like?
It looks like a heavy, opaque, iron-black to brownish-black mineral with a metallic to submetallic sheen, occurring as platy crystals, massive material, or dark grains in black sand.
Ilmenite identified by the community
Recent Ilmenite specimens identified with Rock Identifier.
