Swiss Blue Topaz Gemstones Hardness 8.0. Topaz and citrine are the birthstones of the month of November.
Some blue topaz are indistinguishable from aquamarine with the naked eye.
Most blue topaz is irradiated and heat treated silver topaz , although it is sometimes found naturally. Appearance Swiss blue topaz, also known as electric blue topaz , is the bright vivid form of blue topaz , darker than sky blue topaz , and not as dark as the london blue topaz . Enhancements Blue topaz is usually irradiated and often heated to produce blue color. More information on gemstone enhancements. TPZ424 New 5.65 ct.