Rare Serendibite

How rare is serendibite?
Borosilicate mineral that is very rare indeed in crystalline form. At one time crystalline serendibite was one of the rarest gems in the world and only a handful of specimens were known to exist. Serendibite forms small blue-green, blue-grey to deep blue, sometimes yellow, transparent tabular crystals. The material is strongly pleochroic: yellowish green, bluish green and violet-blue. Cut stones are rare and usually of small size.

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