The American Golden Topaz, a 172-faceted topaz weighing 22,892.5 carats (4.57850 kg), is the largest cut yellow topaz in the world and one of the largest faceted gems of any type in the world. Originating from Minas Gerais, Brazil, it was cut by Leon Agee over a period of two years from an 11.8 kg (26 lb avdp) stream-rounded cobble owned by Drs. Marie L. and Edgar F. Borgatta. It was contributed jointly by the Borgatta owners and by Rockhound Hobbyists of America to the Smithsonian Institution in 1988 and is displayed in the National Museum of Natural History.

I’d have to say this was exceedingly difficult to get an even halfway decent capture of. All the gems are surrounded by heavy glass, which probably doesn’t help for getting good focus. I've changed photos since revisiting the museum as I realized the gem was much lighter than the image I originally posted.

One person had asked if these gems are replicas. They aren’t – they’re the real thing, part of the museum’s priceless gem collection. Some people may remember a gem exhibit I photographed at the Hillwood Estate, jewels previously owned by heiress Marjorie Merriweather Post. She had donated many of her pieces to the Smithsonian, and this is where they’re normally displayed.

Burmese rubies before and after, posted earlier: