Kyanite cabochons. Image by Tamara McFarland, at http://www.mcfarlanddesigns.com/
I first came across kyanite in a jewelry display and was taken in by its beautiful blue color and layered appearance. The name comes from the Greek “kyanos” for blue, though the stone can also be clear, yellow, green, white, and black.
Kyanite is an aluminum silicate (Al2SiO5), like andalusite and sillimanite, the only difference being the crystal structure. Kyanite and other aluminum silicates are used as an ingredient in mullite, which can be found in spark plugs, stove elements, and inside kilns, for its ability to withstand great heat and add strength. When water is added to aluminum silicate, it becomes a clay called kaolin, which can be found in many things including porcelain and as an ingredient in anti-itch and upset stomach medications. You could technically be taking the same substance you are sitting on in the bathroom the next time you have indigestion, and I remember with fondness administering huge pink Kaopectate pills to cows in vet school. (Though truthfully, the kaolin was switched for bismuth subsalicylate and renamed Pepto-Bismol a few years ago in the US). Many South American parrot species are famous for eating kaolin and other clays on cliffs and riverbanks, to aid in their digestion or meet dietary needs.
Gem-quality kyanite is found in all of the inhabited continents but is not very common. Some of the best specimens come from Tibet and Nepal. In general, the bluer and more transparent stones have higher value, and can rival the best sapphires. Kyanite is tricky to cut because it has varying hardness within the same stone (around Mohs 4.5-6.5), as well as a tendency for uneven coloration. This varying hardness makes kyanite sensitive to shock and temperature changes, meaning a piece should not be cleaned with steam or a vibrating bath.
Kyanite is thought to be a positive stone that aligns all of the chakras and is believed to aid in meditation or putting the mind at ease. Similarly, it is thought to bring those with disagreements into harmony and aid in communication. Due to its deep blue color and the belief it could act as a natural compass, it was given to seafarers as a protective talisman.