Quick Facts on Iolite Stone
| Chemical Formula |
: | Mg2Al3O |
| Mineral |
: | Iolite |
| Color |
: | Transparent, violet-blue, light blue, blue, rich
blue-violet stone |
| Hardness |
: | 7.5 |

Iolite is a
silicate of alumina, iron, and magnesia, having a bright blue color
and vitreous luster; cordierite. The name iolite comes from the
Greek ios, which means violet. Iolite is a blue silicate mineral
that occurs as crystals or grains in igneous rocks, only as a result
of contamination of the magma by aluminous sediment. The property
that made iolite so valuable to the Vikings is extreme pleochroism.
Iolite has different colors in different directions in the crystal.
The gemstone changes colors depending upon which angle it is viewed
from.
Iolite, known as the Vikings' compass, due to it's ability to
determine the direction of the sun on overcast days. When the
legendary Viking mariners sailed the wide ocean, they used thin
pieces of iolite as the world's first polarizing filter. Looking
through an iolite lens, they could determine the exact position of
the sun, and navigate safely.
Synthetic magnesium iolite has a low thermal expansion and is used
as a semirefractory material because of its resistance to thermal
shock. Iolite is artistically used in making necklaces, pendants,
rings, bracelets etc. Iolite is commonly cut into traditional
shapes, and its most desirable color is a rich violet-blue. It is
found in the regions of Sri Lanka, Burma, India, Madagascar and
Brazil.