Imperial Topaz Imitation

Natural deep yellow orange pink variety of topaz (imperial topaz) is rare and expensive. The important source for this gem is Ouro Preto, Minas Gerais, Brazil. For now there are no known synthetic imperial topaz, but common imitations such as synthetic spinel, citrine, spessartite garnet and glass are common at the source as well in the international colored stone markets. But lately more synthetic imperial topaz-like corundum (Verneuil/Flame Fusion), rough/cut are seen + for the unsuspecting buyer this could become a problem stone. Standard gemological tests will easily separate common imitations, but the intruders can be a problem when you have to deal with hundreds of stones in a parcel.