Kyanite
Chemical
Formula: Al2SiO5
(Aluminium Silicate)
CAS number: 1302-76-7
Kyanite
is used primarily
in refractory and
ceramic products,
including porcelain
plumbing fixtures
and dinnerware.
It is also used
in electrical insulators
and abrasives. An
interesting property
of kyanite is that
it undergoes an
irreversible expansion
when fired at high
temperature. Kyanite
has also been used
as a gemstone, though
this use is limited
by its anisotropism
and perfect cleavage.
Kyanite is one of
the index minerals
that are used to
estimate the temperature,
depth, and pressure
at which a rock
undergoes metamorphism.
Finally, as with
most minerals, kyanite
is a collector's
mineral.