Long Old Mine Cushion in TGG Lab Garnet 16.5ct

This is a long old mine cushion which I cut in TGG, modeled after Taylor Swift's engagement ring stone.  It weighs in at 16.5ct and measures 15.5x10.2mm.

Note TGG is not completely colorless with a very slight tan hue--this color can get stronger when exposed to UV and then go back down with exposure to normal light.

TGG is a very cool synthetic material. It has the same structure as a natural garnet, but has a composition that would never be possible in nature. The result is a bright and very dispersive gem with optical properties similar to diamond (cubic crystal structure with a lower RI but the same dispersion as diamond), giving it incredible brilliance and fire. It is not, however, grown for gem usage at all, but because of its incredible ability to act as a Faraday rotator. Light passing through TGG in the presence of a magnetic field has its polarization rotated, which might not sound that interesting but is incredible useful for lasers. Lasers shoot out powerful beams but are very fragile, and if any of the light bounces back at them it can quickly burn them out. With TGG it is possible to make a high-efficiency optical isolator that prevents any of that sort of backsplash.  It is almost never faceted as a gem--we are currently likely the only supplier in the world.

It also has bright green fluorescence under 365nm UV!

With a hardness of about 8 on the Moh's scale it is also a good material for use in jewelry.