Sky Blue Topaz, Swiss Blue Topaz, London Blue Topaz are names used in the gem trades to refer to the depth of color. Sky Blue is the lightest while London Blue is the darkest blue.
In mysticism, the topaz is attributed with a cooling, styptic and appetising effect. It is said to dispel sadness, anger and nocturnal fears, to warn its wearer of poisons and protect him or her from sudden death. It is reputed to make men handsome and intelligent and sterile women fertile and happy
The principal sources for topaz are Brazil, Sri Lanka, Russia, Australia, Africa, Mexico and Pakistan.