Rutile is an interesting, varied and important mineral.
Rutile is a major ore of titanium, a metal used for
high tech alloys because of its light weight, high strength
and resistance to corrosion. Rutile is also unwittingly
of major importance to the gemstone markets. It also
forms its own interesting and beautiful mineral specimens.Microscopic
inclusions of rutile in quartz, tourmaline, ruby, sapphire
and other gemstones, produces light effects such as
cat's eye and asterisms (stars). A beautiful stone produced
by large inclusions of golden rutile needles in clear
quartz is called rutilated quartz. Rutilated quartz
is sometimes used as a semi-precious stone and/or for
carvings. This stone is produced because at high temperatures
and pressure, n(SiO2)-n(TiO2) is in a stable state but
as temperatures cool and pressure eases the two separate
with rutile crystals trapped inside the quartz crystals.
Twinning is common in rutile crystals, with a cyclic
twin forming that is comprised of six or even eight
"twins" arranged in a circle. A Rutile Star
is a formation of crystals of rutile in a six rayed
orientation. The crystals grow off of a hematite crystal
and the orientation is caused by its six rhombic faces.