This is 'super' cerium YAG with a brighter glow and more orange color than other normal Ce:YAG. This was custom grown for us with a formula we developed from advanced phosphor research--similar material has probably only ever been grown as powders. Each piece of rough is available individually.
Cerium YAG has been grown since the 50s for its incredible yellow fluorescence. It used to be widely used as a scintillator for detecting radiation but it has largely been replaced by LuAG and GAGG. However, it is still made in powder form for use as a phosphor, a fluorescent pigment used in things like LEDs. Because of this there has been a lot of research on how to improve its glow which mostly hasn't made it into large crystals that can be used as gems. We took some of that research and had a crystal grown with a custom formula, and the result was amazing: an incredible 'super' cerium YAG. It frankly makes pure, scintillator-grade cerium YAG look dim, and goes toe to toe with GAGG and LuAG to the eye. It is also a little phosphorescent!
This is an amazing material to facet, with a good hardness of 8.25, excellent optical properties and little to no trouble in cutting or polishing.
