The Adiel Topaz
This topaz is notable not only for its size, but the work performed on it. Originally mined in Minas Gerais, Brazil, the Adiel Topaz’s rough was a massive 7,796.12 grams. Later, the rough was irradiated into a deep blue color. In this form, the stone came to the attention of a lapidary named Richard Homer.
Homer had been searching for a large scale crystal that would allow him to stretch his skills as a cutter. The Adiel Topaz’s heft satisfied his needs, but was much too large for conventional machines. Shaping the jewel was a five year process that involved custom made devices, and a high risk of bodily strain, particularly on the pavilion facets.
In the end, the finished stone was cut into a trapeze shape with cut corners, weighing in at 20,769 carats, or 4,153.2 grams. It features a total of 117 large facets, with sizable planes on the girdle and smaller ones on the pavilion. Homer documented the process for December 1987’s Lapidary Journal.
The American Golden Topaz
One of the quirks of topaz is its ability to form within pegmatite, stone that allows for other crystals to reach sizes of 2.5 centimeters and more. Given enough time, a rough topaz can achieve jaw-dropping girth. The American Golden Topaz weighs 22,892.5 carats, over four and a half kilos.
Originally from Minas Gerias, Brazil, the jewel’s rough was found inside an 11.8 kg stone and slated to be cut into parts for scientific instruments. When a substitute material was acquired, the topaz went into the hands of Leon Agee, who took two years to fashion the stone’s cushion cut and 172 facets. Afterwards in 1988, the American Golden Topaz was donated to the Smithsonian Institute, where it remains on display.