Iolites

Iolite is the pleochroic one. Look down one axis and it is a deep violet-blue; turn the crystal ninety degrees and the same stone goes pale straw or nearly colorless. Nothing about that changes after cutting, which means the cutter chose the color you see when they chose which way to orient the rough — and it is why two iolites of identical weight can look nothing alike.

Vikings are said to have used thin slices of it to find the sun through cloud. Judge one face-up, in the position it will be set. Standard millimeter sizes, ready for the bench and for our ring builder.