This gemstone is a silicate composed mainly of aluminium and fluorine. Most Topaz stones are colorless, and of little commercial value, but the colored forms are much sought after. Topaz colors range from yellow to orange and brown . The impurity chromium produces pink to red colors and a combination of chromium and color centers (ie a defect in a gemstone’s crystal structure that effects a stone’s color) produces orange topaz.
The rarer blue topaz can also found in nature although most of them are produced by a combination of irradiation and heating treatment.
Although the Topaz is an extremely hard mineral and not easily scratched it does tend to break quite easily along its cleavage lines. For this reason it is more suited for a ring that will not be subjected to harsh conditions.
Topaz gemstones and Citrines are similar in appearance to an untrained eye. It is therefore important to determine, from a reputable dealer, the validity of the stone that you are buying.
One of the most shimmering Topaz gemstones is the Portuguese Imperial Topaz. This stone has a particular way of reflecting light that causes it to shimmer brilliantly – an effect the Portuguese call “brilliance of fire”
Whilst the Imperial Topaz is still technically a Topaz, its internal structure is different in that it contains lots of tiny fractures. For this reason they have to be cut very carefully or they will break. However, because of their brilliant shimmering qualities, these Imperial Topaz gemstones are highly prized. Colors for them range from pale yellow to gold, orange and light sherry brown colors.