Kyanite’s typical habit is a bladed crystal, although it sometimes occurs as radiating masses of crystals. Kyanite is often associated with other metamorphic minerals such as garnet, staurolite, and corundum.
Kyanite specimens have a variable hardness. The long crystals have a Mohs hardness of about 4.5 to 5 if tested parallel to the length of a crystal, and a hardness of 6.5 to 7 if tested across the short dimension of a crystal. The mineral was once commonly called “disthene” which means “two strengths.” (GEOLOGY.COM)