Holmium Color Change YAG Rough

These are color change Holmium laser garnets (Ho:YAG), which are yellow in normal lighting and turn rich pink under fluorescent illumination. 

This is a nice material, holmium yag.  It is used as a laser crystal for far infrared solid state lasers.  In normal lighting it has a light yellow color, light enough to show the brilliant sparkle and dispersion of the YAG.  Under fluorescent illumination it turns a rich pink.  This is fun because it's the exact opposite of Nd+ YAG which is pink in normal illumination but turns colorless or light yellow under fluorescent lighting, allowing for a fun magic trick swapping the colors between them.

The darker crystals appear to be codoped but we aren't certain of the additional dopant.

With a hardness of 8.5 it is ideal for use in all kinds of jewelry.