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Topaz
Greg Polley
Specimen | Catalog Number | Locality | Weight |
---|---|---|---|
Topaz | NMNH G10680 | Brazil | 5.16 ct |
Gift of Mauro Panto in 2011.
Until the 1950s, topaz was known almost exclusively as a yellow to golden gemstone. The highly prized "imperial topaz" is an intense golden to reddish-orange color and is found primarily at Ouro Preto, Brazil. More commonly, topaz is colorless to pale blue or yellow. 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, topaz is recognized primarily as an affordable blue gemstone. This colorless oval topaz gem is 5.16ct and is from Brazil. It has needle-like inclusions of the mineral columbite. Columbite is a heavy oxide mineral that is an ore of niobium and tantalum. The topaz crystal from which the gem was cut grew around the columbite crystals.