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Smithsonian National Museum of Natural History

Imperial Topaz

Photograph of the uncut Imperial topaz (NMNH 116879) and a faceted Imperial topaz (NMNH G3401) from the National Gem and Mineral Collection
Photo by Chip Clark. Click to zoom.
Catalog Number NMNH G3401-00
Locality Minas Gerais, Brazil
Weight 93.6 ct

Gift of Roebling in 1958.

Until the 1950s, topaz was known almost exclusively as a yellow to golden gemstone. But since then, the routine radiation and heat treatment of pale-colored topaz to turn it shades of blue has changed the public’s perception of this gem. To most of the present generation of jewelry buyers, topaz is recognized primarily as an affordable blue gemstone. The highly prized “imperial topaz” is an intense golden to reddish-orange color and is found primarily in Ouro Preto, Brazil. The imperial topaz crystal and gem pictured here weigh 875.4 and 93.6 carats respectively. More commonly, topaz is colorless to pale blue or yellow. Pink or red stones are rare, although pink stones can be produced by heating the golden brown topaz from Ouro Preto.


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