Pure Er:YAG Rough, Erbium Color-Change Garnet chain I cut this as a

I cut this as a special gem at our Open Sauce booth--an extra large stone that resembles a Minecraft emerald

I think the incredible blue glow makes it all worthwhile

Like Ce:YAG and LuAG it is used as a scintillator to help detect invisible radiation

BGO-20 Shards: Used as an acousto-optical modulator

Pure Er:YAG Rough, Erbium Color-Change Garnet chain I cut this as aThese are facet rough of erbium doped YAG, a lab grown garnet used in lasers for both medicine and industry. Erbium YAG has a very obvious color change between different light sources. Under sunlight and cool LEDs it's a nice orange, but it shifts easily, changing color between Cool LEDs (orange), Warm LEDs (yellow), CFL (strawberry pink), and OLED (magenta) as well as under fluorescent lighting and OLED illumination. Sunlight shows an orangeish pink.