Kyanite is a typically blue Silicate mineral that is commonly found in Aluminum rich metamorphic pegmatites and/or sedimentary rock. It is used primarily in refractory and ceramic products including porcelain plumbing fixtures and dinnerware. It is also used in electrical insulators and abrasives. It is definitely a collector’s mineral.
Iolite is the gem variety of Cordierite. Iolite can be light to deep blue and usually has a purplish tinge to it. The name “iolite” comes from the Greek word for violet. Another old name is dichroite, a Greek word meaning “two-colored rock”, a reference to cordierite’s strong pleochroism. It has also been called “water-sapphire” and “Vikings’ Compass” because of its usefulness in determining the direction of the sun on overcast days, the Vikings having used it for this purpose.