THE MATERIAL LIBRARY
Kyanite
An aluminum silicate with strongly directional physical properties.
Colors & patterns
Usually blue with lighter streaks; green and other colors occur.
Typical origins
Sources include Brazil, Nepal, India and several African countries.
Hardness
About 4.5–7, varying by crystal direction
Choosing & setting this material
Its unusual directional hardness and cleavage make cutting challenging. Pendants or earrings offer more protection than exposed everyday rings.
Care & cleaning
Clean gently with lukewarm water, a little mild soap and a soft cloth, then dry. Avoid steam, ultrasonic cleaners, harsh chemicals and sudden temperature changes, especially when treatments are unknown.
Origins above describe typical sources of the material, not the origin of an illustrated or stocked stone. Hardness measures scratch resistance, not resistance to breaking. Confirm the identity and treatments of the actual piece.
Further reading: Material reference · GIA: gem treatments