Sapphire, a buyers guide.
Birthstone of September, also known as corundum, or aluminum oxide.
Ancient Persians thought the world sat on a giant sapphire that reflected light off its surface to make the sky blue. Sapphires have been sacred to many
religions. Some say that Moses was presented with the ten commandments on slabs of sapphire.
Its name is somewhat misleading as it’s from the Greek, sappheiros, meaning blue stone’ .
When pure, sapphire is colourless, it’s colour derived from transitional elements caught within the crystal structure. Blue is caused by iron & titanium, orange by iron & chromium, purple by vanadium, yellow and green by iron only. Pink is caused by chromium only, becoming red with a greater concentration of chromium, then being called ruby.
The most valuable sapphires are cornflower blue, from Kashmir, the record price was set in April 2007 at Christies in New York when an 22.66 ct blue Kashmir sapphire sold for $3,064,000, or $135,216 a carat.
Stones from Burma, Sri Lank and Madagascar are also well-regarded.
As with all gemstones the price of a sapphire can vary a massive amount. Sapphires have been simulated or made in a lab for over 100 years, these stones are easy to distinguish, and often used in horology as well as the scientific and electronic industry.
The ideal sapphire is a rich vibrant blue, bright, clean and cut well to maximize its beauty. Unless stated otherwise, sapphires are heat-treated to make the colour more even and richer; this treatment has been used since roman times. It is fairly easy to look at a sapphire under 10 times magnification to see evidence of heat treatment.
I am often asked for very dark blue stones, generally from Australia, not expensive and in my opinion not very attractive. They look black, only showing blue under very intense light. I have assumed these are desired as it is how the “princess Diana ring” appears in photographs. When you see a nice bright vibrant blue stone, you will appreciate its value.
The price of fancy coloured sapphire fluctuates with fashion and demand, the criteria not so strictly measured, more subjective than blue stones. These fancy colours come from numerous sources around the world, until the late 1990’s pink sapphires were relatively rare, then a new source was found in Madagascar, so they became more widely available, and were very popular. The green of sapphire isn’t a vibrant green like emerald, but more towards the sage. I have a lovely range of natural fancy colour sapphires, and love opening packets, when discussing a commission, the reaction is always the same, I never knew they came in such amazing colours… don’t they look delicious…
The only colour of sapphire to be given it’s own name is Padparadscha a delicate pink-orange to orange-pink hue, the named being derived from the Sanskrit padma (lotus); raga (color), a color akin to the lotus flower.
It is fairly common for sapphires to show different colours in different light, know as pleocloric. I have some amazing colour change stones, they change from blue to purple to greenish, then red under UV.
At hardness 9, sapphire is suitable for use in a variety of jewellery, especially engagement rings. Sapphires have come to symbolize truth, sincerity and faithfulness.
The 45th wedding anniversary is Sapphire.