RocksdayRutile vs Tourmaline
How to tell them apart
Titanium dioxide, forming red-brown to black striated prisms or golden needles inside quartz.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
A boron-bearing silicate found in more colors than almost any other gem. Black schorl is the most common form.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Streak (rub on unglazed porcelain): Rutile leaves a pale brown streak; Tourmaline leaves white.
- Heft: Rutile feels noticeably heavier for its size (specific gravity 4.2–4.3 vs 3–3.3).
Key differences
- Tourmaline is lighter and has a triangular cross-section.
Side by side
| Property | Rutile | Tourmaline |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 6–6.5 | 7–7.5 |
| Luster | Adamantine to submetallic | Vitreous |
| Streak | Pale brown | White |
| Colors | Red, Brown, Black, Gold | Black, Green, Pink |
| Crystal system | Tetragonal | Trigonal |
| Specific gravity | 4.2–4.3 | 3–3.3 |
| Formula | TiO₂ | Complex borosilicate |
| Found in | Graves Mountain, Georgia; Minas Gerais, Brazil | Mount Mica, Maine; San Diego County, California |
Properties that are the same for both are grayed out.
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 →How to identify tourmaline
- Long prisms with lengthwise grooves (striations).
- Rounded-triangle cross-section when broken across.
- Hard — scratches glass.
- Gem crystals can change color from end to end ('watermelon').
Crystal system: Trigonal
Full Tourmaline guide →More comparisons
Could you tell them apart from a blurry close-up?
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