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Photograph of a football-shaped blue topaz (G8990) from the National Gem Collection
Photo by Chip Clark
Hover over color tiles above to learn what this object tells us about the history of the Earth
About this object
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 deep blue has changed the public’s perception of this gem. To most people today, topaz is recognized primarily as an affordable blue gemstone. The highly prized imperial topaz is intense golden to reddish-orange in color. 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, Brazil. This football-shaped blue topaz gem from Minas Gerais, Brazil, weighs 7,033 carats. Like most blue topaz, its stable color is the result of irradiation and heat treatment; originally this topaz was probably colorless or very pale yellow-brown.
denotes specimens currently on exhibit
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