Before buying Kyanite, one should look for 3C’s: Cut, Color and Clarity. Kyanites are normally transparent and have a very beautiful cut, which gives it an amazing shine and luster. The best said color of kyanite is Bluish-Purple.
There is no substitute of Kyanite, as kyanite itself is a substitute of Blue Sapphire but if required it can be worn in place of Amethyst, Iolite, Tanzanite, Blue Topaz and Lapis Lazuli.
Kyanite can dissolve in water if left submersed in it for a long period time.
Its hardness varies vertically and horizontally. Vertical hardness ranges from 4.5 to 5.5 and the horizontal hardness ranges from 6 to 7.
It is said that, it help to recall the past life.