Daily Archives: October 6, 2011

Kyanite – A Polymorph with Differential Hardness

Gemmologists like kyanite, lapidaries do not!  It is a gemstones that appears on most Professional Gemmologist’s theory or practical exams.  Give an example of a gemstone that shows differential hardness?  Name a polymorph of andalusite and sillimanite?  Name a gemstone that has a bladed habit?  The answer to all those questions is kyanite!

Kyanite from Wikipedia by Aelwyn

Kyanite Photo by Aelwyn

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