These are lab created light gray laser garnet facet rough. Pieces are labeled with their gram weight and letter in the photo and they can be purchased individually.
This is a new type of YAG (yttrium aluminum garnet) that we recently got in. It has an unusual light grey color, or rather it is zoned with a darker gray center with a streak of blue-purple), a much lighter gray rind and bright pink fluorescence under a long wave 365nm light. These were grown by the HDSM method and come from the 'prow', the tip of the crystal that concentrates various impurities. I don't know what causes this color but it is very unusual. The crystal was apparently grown for use in lasers.
YAG is an excellent material to facet, incredibly easy to cut and polish and with a high hardness of 8.25-8.5, an RI of 1.83 and good dispersion which makes for very lively stones even before the color factors in. It is suitable for use in all kinds of jewelry.
