Identification guide · Oxide Minerals
How to Identify Ilmenite
Ilmenite is usually black, iron-black, and brownish black with a metallic luster and is opaque. It has a Mohs hardness of 5.5. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Its streak is black to brownish red. It is most often confused with Rutile, Hematite, and Magnetite; the tests below separate them.
Ilmenite identification checklist
| Color | Black, Iron-black, Brownish black | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Metallic | Turn it under a lamp: a true metallic shine reflects like polished metal and stays opaque at thin edges. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 5.5 | It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. |
| Streak | Black to brownish red | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | None | |
| Fracture | Conchoidal to uneven | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 4.7 | Very heavy, metallic heft (specific gravity about 4.7). |
| Crystal system | Trigonal |
Extra tests for Ilmenite
Magnet test. Weakly magnetic compared with magnetite; a strong magnet responds faintly.
Ilmenite look-alikes and how to tell them apart
Rutile is harder (Mohs 6.5) than Ilmenite (Mohs 5.5), so Rutile will scratch Ilmenite and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Ilmenite vs Rutile →
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Ilmenite vs Hematite →
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Ilmenite vs Magnetite →
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Ilmenite vs Pyrolusite →
Field tips
- Look for a black, opaque, metallic to submetallic mineral that is dense and only weakly magnetic.
- Ilmenite leaves a black to brownish-red streak and lacks distinct cleavage.
- Distinguish it from magnetite by its much weaker magnetism and from hematite by its black rather than red streak.
Ilmenite identification FAQ
How can you tell if a rock is Ilmenite?
Check the color (black, iron-black, and brownish black), the metallic luster, a Mohs hardness of 5.5 and a black to brownish red streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Ilmenite?
Ilmenite has a Mohs hardness of 5.5. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
What is the difference between Ilmenite and Rutile?
Ilmenite (Mohs 5.5, metallic luster) and Rutile (Mohs 6.5, adamantine luster) look alike, but hardness, streak and heft usually separate them. See the full Ilmenite vs Rutile comparison for a side-by-side table.
Is Ilmenite worth anything?
Entry-level Ilmenite specimens sell for around $5, typical collector pieces about $35, and premium examples $200 or more depending on size, quality and locality.
What color is Ilmenite?
Ilmenite is most often black, iron-black, and brownish black. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
