Blue Topaz

Blue topaz is a popular blue coloured gemstone which is usually faceted for use in ladies jewellery, it’s also one of the birthstones for the month of December with the other being turquoise.  There are three varieties of blue topaz, Sky, London and Swiss and the shade of blue that each exhibits is slightly different.  Sky Blue topaz is the lightest of the three and possibly the most well known and it can occasionally be mistaken for aquamarine.  The London and Swiss blue varieties are a much deeper colour and because they take longer to treat, they can also be considerably more expensive.

Whilst natural blue topaz is available, it is extremely rare hence the vast majority of stones are heat treated in order to obtain the colour of choice.  In fact most natural topaz tends to be clear and only once heated does it begin to change colour.  As well as various shades of blue, topaz can also turn pink and yellow and each colour or shade of colour is determined by the the type of treatment the stone’s exposed to and also the specific temperature.

Although the variation in colour in blue topaz is minimal within each of the three blue varieties, finer grade stones will clearly be more spectacular and the difference between a lower grade and finer grade stone will be easy to see even by those with minimal expertise in this field.

The heating of gemstones is nothing new and it’s a process that has been around for thousands of years.  It would be pretty accurate to say that some of the heat treatments that are used are as old as the gem trade itself. Pliny the Elder [23-79 AD] ancient Roman author, naturalist and philosopher wrote about “giving crystal quartz the colour of emeralds” and “how to change one gemstone into another” which is a reference to the artificial colouring of natural gemstones.

The application of heat in a controlled environment will enhance or change the colour of many gemstones.  Different treatments are used for different stones and whilst some may see this as cheating, many of the world’s finest rubies, sapphires and emeralds have been heat treated to enhance or change their colour.  A ruby which has not been heated is considered to be extremely unusual.  Amethyst is another stone which is often heated in order to enhance or change its colour and due to the fact that natural citrine is so rare and hence expensive, the vast majority of this yellow coloured quartz is actually heated amethyst.

Stone Mania is a London based mineral dealer who imports, wholesales and retails crystals, rocks, minerals and ladies gemstone pendants from Africa, Asia and the USA.