Swiss Blue Topaz is the trade name used to describe a vivid medium to medium-dark blue hue of Topaz. This gem is a great alternative to Aquamarine, with more intense color at a lower price. While blue Topaz is popular and plentiful in the jewelry market, natural occurring blue topaz is very rare. Colorless topaz is treated with irradiation and heat to produce the characteristic blue color. Clean with warm, soapy water. Avoid use of ultrasonic and steam cleaner. Treat with extra care due to possible cleavage.