These are facet rough of an unusual laser garnet: Er-doped YSGG (Yttrium Scandium Gallium Garnet).
This is a new material for us, an exotic garnet used in far infrared medical lasers. It is used for similar applications as Er:YAG but used far less often. Its color is also similar to Er:YAG but with a slightly richer color and a slightly more dramatic color change. It also has a high density relative to YAG. It's a rarity that should cut some amazing gems!
