Pure Er:YAG Rough, Erbium Color-Change Garnet Stone:Edge, 12.5×11.8×10.7mm, 5.02g It's the hardest gem that

It's the hardest gem that can feasibly be cut into a die and it is more brilliant than a diamond

This stone has a few bubbles and needles

Soviet Laser Garnet: Pink-orange experimental laser garnet grown in the Soviet Union

This is a custom cut pink and yellow lab sapphire done in a pixel cut tablet heart

The blue also gets more vivid--the frosted faces make it look greyer than it is

Pure Er:YAG Rough, Erbium Color-Change Garnet Stone:Edge, 12.5×11.8×10.7mm, 5.02g It's the hardest gem thatThese 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.