Ideally, minimum weight of Blue Topaz which should be worn is calculated according to your body weight. (8-10 kgs of body weight denotes 1 carat)
Preferably it should be of high clarity with Deep Sky Blue in color.
There is no as such substitute of Blue Topaz. In fact, Blue Topaz itself is a substitute of Blue Sapphire. It can also be worn in place of Amethyst, Iolite and Tanzanite.
Blue Topaz makes a very beautiful 16
th Wedding Anniversary gift.
It is sometimes mistaken as Blue Diamonds because of its superb cut and clarity.
The biggest Topaz mined is 272.155 kgs and it kept in the Museum of Natural History in New York City.
The Marbella Topaz is the biggest Blue Topaz, which weighs 1.645 kgs.