A red-to-black oxide consisting
of impure titanium (IV) oxide (TiO2),
a titanium ore of widespread occurrence, found in igneous and metamorphic
rocks and quartz veins. Rutile occurs as long prismatic and needle-like
crystals in the tetragonal system and as granular masses. It has a metallic
luster and is britlle. It is used to color porcelain and as a gemstone.
Hardness 6–6.5; relative density 4.2.
|Wine-red rutile crystals from Binn Valley, Switzerland
(Size: 2.0 × 1.6 × 0.8 cm). Image source: Wikipedia
AND PLANETARY SCIENCE