Rutile
Rutile is a titanium dioxide mineral known for its high luster, deep reddish-brown to black color, and slender prismatic or needle-like crystals. It frequently occurs as golden or coppery needle inclusions within quartz, producing the popular rutilated quartz.
Rutile properties at a glance
| Type | Oxide Minerals |
|---|---|
| Chemical formula | TiO2 |
| Mohs hardness | 6.5 |
| Crystal system | tetragonal |
| Luster | adamantine |
| Streak | Pale brown to yellowish |
| Cleavage | Good on {110} |
| Fracture | Conchoidal to uneven |
| Specific gravity | 4.25 |
| Transparency | translucent |
| Common colors | Reddish brown, Black, Golden yellow, Red |
| Rarity | common |
Geology & background
Rutile crystallizes as an accessory mineral in igneous and metamorphic rocks and in hydrothermal quartz veins, and it also concentrates in placer sands because of its hardness and density.
Rutile was named in 1803 from the Latin word for reddish, describing its typical color. It became economically important in the twentieth century as a primary source of titanium metal and titanium dioxide pigment.
How to identify Rutile
- Look for very high adamantine luster, reddish-brown to black color, and slender striated prismatic crystals.
- Distinctive knee-shaped or heart-shaped twins are common and help confirm rutile.
- Golden needle inclusions in clear quartz are a strong indicator of rutilated quartz.
Where Rutile is found
Rutile occurs worldwide in metamorphic rocks, quartz veins, and placer sands, with notable specimen localities in Brazil, the United States, Switzerland, Norway, Australia, and Madagascar.
How much is Rutile worth?
| Entry-level specimen | $10 |
|---|---|
| Typical collector specimen | $80 |
| Premium specimen | $600+ |
Value depends on crystal quality, luster, color, locality, and whether the piece is fine rutilated quartz.
Common uses
- Titanium metal ore
- White pigment production
- Gemstone inclusions in rutilated quartz
- Welding rod coatings
- Collector specimens
Interesting facts
- Rutile is the most common and stable natural form of titanium dioxide.
- Fine golden needles of rutile inside clear quartz create the prized gem material called rutilated quartz.
- Rutile has one of the highest refractive indices of any natural mineral, giving it intense luster.
- It is a major ore of titanium, a metal valued for its strength and light weight.
Care & safety
Rutile is fairly hard and durable but its crystals can be brittle and slender needles may snap.
Avoid inhaling dust. Do not cut, grind, or polish unknown specimens without eye protection and a proper respirator.
