Being a jeweller I often get the question “what’s the birthstone for so and so month?” and I’ve been meaning to do a monthly post with birthstone information for ages. September’s birthstone is sapphire which is a stone that I use a fair bit these days, so I thought I’d finally get started on this birthstone series. I’m hoping to write a brief summary for each month’s special stone and hopefully show a few pieces I’ve made with them.
As always it’s lovely to be able to personalise a gift, and incorporating a birthstone is of course a great way to do this. So, if you know someone who is lucky enough to have their birthday this month, or just fancy the low down on sapphires, read on!
Sapphires belong to the gem family called corundum, together with rubies, and have a trigonal crystal form. Gemstones are all given a Mohs grading for hardness and sapphires have a score of 9 Mohs, making it the second hardest gem after diamond. To find out about what Mohs scale means and see a list of other gemstones go and check out the Wikipedia listing for Mohs.
The hardness of sapphire means that it can stand up to wear and tear and be used in jewellery that is worn on a daily basis, and in exposed pieces such as rings. The metal that is used to set the stone is likely to wear down before the stones do, which is why it’s important to check settings now and then to stop the loss of precious stones. For the jeweller the hardness of sapphires means that they are relatively easy to work with and quite forgiving when setting, and they can be cleaned using ultrasonic and steam cleaners.
Origins and colours
The blue sapphire is the most widely known colour, but sapphires come in all sorts of colours; grey, black, brown, orange, pink, yellow, green and so on.
Sapphires can appear from transparent to opaque and the wide variety of colours of sapphires means that there is a sapphire for everyone! Quite literally, as there is also a wide range of prices, from the opaque ones at the lower end, to the very clear and clean, high quality sapphires at the higher end. For example, Burmese blue sapphires with their very uniform blue brilliant colour, are highly priced and usually only found in high end, luxury jewellery.
Sapphires are found in many places across the world and the different geographic areas produce specific colours of sapphires.
Blue sapphires can be found in Africa, Australia, Brazil, Burma, Pakistan, Sri Lanka, Thailand and the U.S.. Pink sapphires get their colour from the Chromium they contain, and can be found in Madagascar, Myanmar (Burma), Sri Lanka and Tanzania, while the striking orange-pink coloured Padparadscha variety is found in Sri Lanka, Vietname and East Africa. The yellow, green and purple coloured sapphires can be found in Australia, Myanmar (Burma), Sri Lanka, Tanzania, Thailand and the U.S..
Sapphires can also be colourless and this variety is found in Sri Lanka. Finally, in Tanzania and Thailand, you can find colour change (show different colors in different light) sapphires.
Treatments and pricing
Sapphires are priced according to colour, clarity, size and cut. A natural untreated sapphire carries a high price and is very sought after. For example, blue sapphires should be an intense blue with purple tones, show no colour zoning (variations or stripes), and no grey or green colouring. These inclusions (grey, green shades or colour zoning) can however also be a sign that a stone hasn’t been treated to improve its colour and uniformity.
Heat treatment is a common practise used to improve colour, and this can make it hard to be sure of the quality of a sapphire. Heat treated stones, although often displaying gorgeous vibrant colours, are less valued, but can be hard to spot and are sometimes sold as the real thing, as high quality untreated, natural stones. Heat treatment combined with deliberate addition of certain impurities (e.g. beryllium, titanium, iron, chromium or nickel), which are absorbed into the structure of the sapphire, is also common, and is sometimes called “diffusion” in the gem world.
Get your hands on some gorgeous sapphire!
Personally I love sapphires! They come in so many fabulous colours and I particularly like the opaque varieties, as I like the look of less “perfect” stones, and because they are not quite as pricey as the transparent, high quality ones. The fact that they are so hard is a bonus when working with them and I also know that they will wear well with a low risk of breaking once worn by my customers. Pretty much any type of jewellery can be made with them, daily wear and tear is no match for sapphires!
I usually have some pieces in stock using sapphires and they can of course also be made to order. I have some lovely suppliers that I can trust to source pretty much anything that you would like, within reason of course!
The Jeweller’s directory of gemstones; Judith Crowe, 2006, Quarto Publishing plc.
Sapphire on Wikipedia
Hexagonal Crystal Family on Wikipedia