Tuesday, September 6, 2011

Sapphire is the Gemstone of the Week

Sapphire is the birthstone for September and the gemstone of the week. Sapphires are the most precious and valuable of the blue gemstones, although they come in many other colors. Sapphires are made from the mineral corundum, like rubies, and are the second hardest gemstone after diamonds. On the Moh scale, they are a 9. All corundums that aren't rubies, are classified as Sapphires.

Padparascha is a pink orange variety of Sapphire that is very rare and highly valued. The word comes from the Sinhalese word for lotus blossom. Along with rubies, they are the only type of corundum to be given their own name rather than being called a particular color of Sapphire. The original mines are in Sri Lanka, but other deposits are found in Viet Nam and Africa. It is often higher priced than even the finest blue Sapphires. More Sapphires of the color have appeared in the market lately due to a new treatment called “lattice diffusion”.

Fancy color Sapphires are how the green, yellow and pink varieties are often classified. Pink Sapphires deepen in color as the amount of chromium increases. The deeper the pink, the higher the value, as the color then trends towards ruby.

 Star Sapphires are stones that exhibit a star like phenomenon known as asterism. This is caused by intersecting needle like inclusions that cause a six rayed star to appear when viewed with an overhead light source. The Black Star of Queensland is believed to be the largest Star Sapphire ever mined, weighing in at a whopping 733 carats. Star Sapphire value not only depends on the size of the stone, but the body color and the intensity and visibility of the star.
Sapphires are treated by several methods to improve the clarity and color. Heat treatment is the most common method. Evidence of heat treating these stones goes back to Roman times. Un-heated stones are very rare and will often be accompanied by a certificate from an independent gem lab stating that there is no evidence of heat treatment.
Diffusion treatments are controversial as they add elements to the stone to improve color. Beryllium is diffused into a stone using very high heat, just below the melting temperature of the stone. Orange Sapphires were originally created with this process, but it now extends to all colors. It is unethical to sell these treated stones without disclosing this treatment fact and the price should be much lower than an untreated or just a heat treated stone. Treating stones with this diffusion method is frowned upon because if the stone chips or is repolished or refaceted, the color layer can be removed. Treated stones are very difficult to detect and it is recommended that you get an certified gemological lab certificate before investing in the stone. The Federal Trade Commission states that any sort of treatment on a stone that significantly affects the value of a stone, must be disclosed.

It is believed that Blue Sapphires inspires creative expression, intuition, and meditation. Green Sapphires are believed to bring luck, Pink Sapphires encourage love, loyalty and generosity,Padparascha sapphires augment wisdom, optimism and friendliness. It is also believed that Star Sapphires develop independence and balance.

A piece of pink Sapphire rough and some pink Sapphire beads that I have. 

The Logan Sapphire Brooch

The Black Star of Queensland