Kyanite has been used as a semiprecious gemstone, which may display cat's eye chatoyancy, though this use is limited by its anisotropism and perfect cleavage.

How can you tell real kyanite?

6. How to know your Kyanite is real? Kyanite has a distinct property called anisotropism. you will notice variable hardness in the same crystal and a habit of blotching or streaking of color in a single piece of jewelry.

Is Pleochroic a sillimanite?

Color/Pleochroism

Vitreous luster and white streak.