Among the most highly desired of all naturally coloured Topaz, the rich, golden yellow Imperial Topaz is particularly prized. Before heat treating became the norm, Imperial Topaz was one of only a handful of colours to be found in Topaz.
When you see a golden yellow Topaz advertised as Imperial Topaz, it is not generally enhanced by treatments. Minas Gerais, in Brazil, is where the most naturally coloured Imperial Topaz comes from.
In the 18th century this gem was hugely popular in Imperial Russia and it is through this association that the gem most likely received its name.