Cerium YAG Facet Rough, Vivid Yellow Lab Garnet

This is classic cerium-doped YAG (Yttrium Aluminum Garnet) with a bright yellow base and strong yellow fluorescence.

Cerium YAG is one of the most classic gems of science.  Cerium gives YAG a canary yellow base color and incredible yellow fluorescence--it is so beautiful that it was first used in jewelry before a scientist realized that it had potential as a scintillator.  Scintillators use strong fluorescence to convert high energy wavelengths to visible light that can be more easily detected, and cerium YAG was the first of the garnet scintillators, though it has since been mostly replaced with denser GAGG and LuAG.  It isn't as bright as GAGG or LuAG but it still has a vivid yellow look and is very impressive to the eye.

This is an amazing material to facet, with a good hardness of 8.5, excellent optical properties and little to no trouble in cutting or polishing.