Rubies and Sapphires

Did you think a ruby was a ruby and a sapphire was a sapphire? Well, almost, but not quite!
Both are nine out of ten for hardness, they have the same triagonal crystal structure, the
same chemical formula Al2 O3. They have the same specific gravity and the same refractive index, and they are both formed of corundum. So how do the experts tell the difference?

Colour is obviously a give-away, the presence of titanium will give you a blue sapphire,
chromium will give you a pink sapphire, and a lot of chromium will give you a ruby. To tell the difference you really need an expert with years of experience who, by constant handling and comparing of stones, will be able to judge. We are in the realms of an expert eye who can differentiate between the secondary hues, tones and maximum colour saturation of the stone. And, in the case of rubies and pink sapphires, the fact that pink is not a distinct hue, but a light-toned pale red compounds the problems.

One clear indication, providing you have purchased from a reputable source, is price. Rubies are very much more expensive and go to stratospheric prices for stones of 2 carats or more; sapphires, pink or otherwise, do not command such figures.

Sapphires come in all colours, except red of course, and there are even colour changing stones available on the market. The best blues come from Sri Lanka, and are known as Ceylon sapphires. Historically, the best rubies have come from the Magok mine in Burma, now called Myanmar; typically, these rubies are purple/red. Thai rubies have a more orange/red colour, and I have recently used some excellent Tanzanian rubies with superb clarity and a stained-glass window red.

Rubies can have inclusions called silks and, when heavily included, can be cut to form the
most stunning star rubies. About 95% of rubies have been heat treated to enhance colour. This treatment is undetectable in some stones such as tourmaline and aquamarine, but is detectable in rubies and can reduce the value by around 35%. Other treatments are glass filling fractures in the stone and diffusion.

A paler red ruby or a fuchsia pink sapphire? Sapphire for me every time!

Should you have any enquiries or jewellery requirements, please call me.

StrawberryWood

0800 917 8684
P.O. Box 7491, Kettering, N16 6HU
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www.strawberrywood.co.uk

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