Kyanite is very rare as a faceted gem, especially if free from inclusions and flaws. The material is extremely difficult to cut because of its perfect cleavage and the extreme variability in hardness in different directions in the same crystal. The name Kyanite derives from the Greek word “kyanos,” meaning “blue.” It is also spelled “cyanite” and known as disthene. It is a cut stone that is pale to deep blue or white, grey, or green.