RocksdayCassiterite vs Rutile
How to tell them apart
Tin dioxide, the main ore of tin — heavy, shiny brown-black crystals.
Photo: CarlesMillan, CC BY-SA 3.0
Titanium dioxide, forming red-brown to black striated prisms or golden needles inside quartz.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Streak (rub on unglazed porcelain): Cassiterite leaves a white to pale brown streak; Rutile leaves pale brown.
- Heft: Cassiterite feels noticeably heavier for its size (specific gravity 6.8–7.1 vs 4.2–4.3).
Key differences
- Rutile is lighter and more striated.
- Cassiterite is much heavier and usually lacks striations.
Side by side
| Property | Cassiterite | Rutile |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 6–7 | 6–6.5 |
| Luster | Adamantine to submetallic | Adamantine to submetallic |
| Streak | White to pale brown | Pale brown |
| Colors | Brown, Black, Yellow | Red, Brown, Black, Gold |
| Crystal system | Tetragonal | Tetragonal |
| Specific gravity | 6.8–7.1 | 4.2–4.3 |
| Formula | SnO₂ | TiO₂ |
| Found in | Cornwall, England; Llallagua, Bolivia | Graves Mountain, Georgia; Minas Gerais, Brazil |
Properties that are the same for both are grayed out.
How to identify cassiterite
- Very heavy for a non-metallic mineral.
- Brown to black with a brilliant luster.
- Light-colored streak despite the dark color.
Crystal system: Tetragonal
Full Cassiterite guide →How to identify rutile
- Deep red to black prisms with lengthwise striations.
- Very bright, almost metallic luster.
- Often as golden hair-like needles inside quartz.
Crystal system: Tetragonal
Full Rutile guide →More comparisons
Could you tell them apart from a blurry close-up?
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