September Birthstone: Sapphire

Sapphires have an esteemed history. Tradition holds that the tablets containing the Ten Commandments were composed of sapphire, so strong that a hammer swung against them would be smashed to pieces. The ancient Persians believed that the earth rested on a giant sapphire and its reflection coloured the sky. Many other cultures have believed that sapphires imparted healing and calming properties

Sapphires have been worn by royalty throughout the ages as a symbol of good fortune, virtue, wisdom and holiness. Princess Diana, Princess Anne and now Princess Katherine all received sapphire engagement rings and the British Crown Jewels are full of large blue sapphires, the symbol of pure and wise rulers.

Sapphire is the birthstone of September. Since sapphire symbolizes sincerity and faithfulness, it is an excellent choice for an engagement ring. It is also the traditional wedding anniversary gift for a couple's 5th and 45th year.

While we traditionally think of Sapphires as being only blue stones, they actually come in all colours from black to white.  Corundum is second only to Diamond in terms of its physical hardness, (although exhibiting only  1/140th of the hardness of Diamond), this hardness (9 on the Moh's scale) in relation to all other gemstones has ensured Sapphires position with Ruby and Emerald  as one of the so-called "precious gems".

Sapphire is the birthstone for those whose birthday falls in September, and for those born under the star sign of the Taurus.

In Blue Sapphire the causal agent is trace amounts of Iron or Titanium, a  violet hue being caused by the presence of Vanadium. When the trace content of Iron is very low, yellow and green tones are produced. While the inclusion of Chromium in the lattice produces a pink colour in the stones. Blue is however the most famous and desired of the sapphire colours. The prized Kashmir and Burmese Sapphires have a deep intense almost velvety blue colour, and represent the pinnacle of colour perfection.

Padparadscha from the Singhalese word for  lotus flower, is a very rare sapphire which exhibits two colors simultaneously, pink and orange, and like Ruby and unlike all the other fancy coloured Sapphires has its own name. This being due to its rarity and value.

Purple is another rarer colour for Sapphire, being  found in Sri Lanka and Tanzania. In these deposits Iron and Titanium which normally produce the common blue colour, has under specific concentrations and conditions caused the purple hue of the stone.

Colourless or white Sapphires are rare as faint shades of colour (typically blue and pink) are nearly always present.

Many of the fancy coloured Sapphires are under microscopic examination merely combinations of banding in two distinct colours. Green for example is actually the result of closely space blue and yellow colour band within the stone.

Sapphire like their cousins Rubies are commonly heat treated to enhance their colour and to even out or totally remove "silk". While initially only stones of a lower quality were treated in this way, estimates coming for South East Asia indicate that heating is now carried out of about 95% of all rough material, as part  of an industry accepted enhancement technique. Heat treatment is used specifically to improve and even out the colour in Sapphires, and when done at a moderate heat will reduce the presence of needles. At higher temperatures needles, specifically of Rutile are completely removed by a process of melting and re absorption. These heat treatments enhancements  typically occur around temperatures of 500  - 1800 °C, in computer controlled electric furnaces. Some cutting houses still use the older process of low tube heat, when the stones are heated over charcoal at a temperature of about 1300 °C  for 20 to 30 minutes, a process know in the trade as "Chanthaburi cooking". The silk is only partially broken as the color is improved, imbibing the stone with a richer luster, and better colour.

Looking for a great Sapphire?  Go to our webiste and online shop:  www.touchstonegems.co.za