Judging quality
Look for deep sapphire-blue color zoning, glassy bladed faces and intact tips. Kyanite splits easily along its length, so undamaged blades command a premium.
Silicate
Kyanite
A remarkable mineral with two different hardnesses in one crystal: about 4.5 along the blade and 7 across it. Blue blades from Brazil and Nepal are the classic specimen.
Care
Splinters along its length. Handle by the flat faces; rinse and dry.
History & lore
Its directional hardness made it a standard classroom demonstration of anisotropy for over a century.
Cultural history, recorded as tradition rather than as medical or scientific claim.
Common questions about Kyanite
- What is Kyanite?
- A remarkable mineral with two different hardnesses in one crystal: about 4.5 along the blade and 7 across it. Blue blades from Brazil and Nepal are the classic specimen.
- How hard is Kyanite and what is it made of?
- Kyanite is a Silicate-family mineral with the composition Al2SiO5. It crystallizes in the triclinic system and rates 4.5-7 on the Mohs hardness scale. It occurs in blue, black, green, orange.
- Where does Kyanite come from?
- Notable localities for Kyanite include Brazil, Nepal, Zimbabwe, India.
- How do you tell good Kyanite from filler?
- Look for deep sapphire-blue color zoning, glassy bladed faces and intact tips. Kyanite splits easily along its length, so undamaged blades command a premium.
- How do you care for Kyanite?
- Splinters along its length. Handle by the flat faces; rinse and dry.
See it in person
Photographs only go so far
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.