Yellow topaz is a fluorosilicate of aluminum with hydroxyl. The yellow color is the most commonly found and is caused by impurities, as pure topaz is colorless. Yellow topaz is also known as Imperial topaz, and Brazilian Imperial topaz can be a brilliant shade of yellow.
Topaz is most often found around volcanoes and is found all over the world. Localities include Germany, the United States, Brazil, Sri Lanka, Australia and Nigeria.
Topaz has a ranking of 8 on the Mohs hardness scale, with diamond being a 10. It has a vitreous luster and is a fairly tough material. Specimens can be boulder-sized, and one of the largest pieces of topaz ever found is the American Golden Topaz, which is a yellow topaz that weighs 22,892.5 carats and has 172 facets.
Folklore that concerns the topaz claims that it was one of the jewels that made up the foundations of the gates to New Jerusalem. It was also the gemstone dedicated to Jupiter by the ancient Romans. It is supposed to have a cooling effect and is believed to banish negative emotions. It protects its wearer from poisoning and sudden death, and it makes barren women fertile.
Topaz is also the birthstone for November, though some believe the November birthstone is specifically orange, or precious topaz.