London Blue Topaz Gems
In general, blue topaz
is one of the most popular and best value gemstones
available today. Since natural blue topaz is extremely rare and often pale in color, the colors of London blue, Swiss blue, Electric blue and Sky blue topaz
are formed through an artificial irradiation enhancement process. London blue topaz is considered 'natural topaz' although it has been treated, and through enhancement, it remains as one of the more affordable gemstones
on the market, even in larger sizes; especially when compared to the prices of other popular blue gemstones
, such as aquamarine, blue zircon and most especially, blue sapphire. It is in fact, the second most popular blue gemstone on the market, next to blue sapphire. Topaz is one of December's official birthstones
. The topaz family of gemstone is indeed one of the most important gems in the world of colored stones. It is one of the hardest gems available (8 on Mohs scale), although its perfect cleavage can leave it vulnerable to hard knocks and blows, a trait it shares with diamond.
Blue topaz is available in a wide range of vivid blue hues, and not only does it occur with excellent transparency, it also exhibits a striking vitreous luster when cut and polished. Of all the many different colors of blue topaz, London blue is the most prized and usually the most valuable. However, since all blue topaz is relatively affordable, price differences between other color varieties are usually quite minimal. Blue topaz is traded under specific color varietal trade names such as Sky-blue, Swiss-blue and London-blue. London blue is the deepest of blue topaz colors and is described as being a medium to dark grayish-blue, sometimes referred to as 'inky' blue. London blue topaz gems will often have a slight secondary greenish tone when viewed from certain angles.