No one ever thought Aluminium Oxide wouldd look this good! Ruby’s chemical composition is Al2 O3, with the colouring agent Chromium. It belongs to the Corundum family with her twin sister Sapphire. She’s also another variation of Aluminium Oxide! The name ruby comes from the Latin word ruber meaning “red”.
Some of the popular colours of ruby include the “Pigeon Blood”, “Vivid Red”, “Pinkish Red”, “Purplish Red”, “Orange Red” & “Brownish Red” (arranged in the order of preference , “Pigeon Blood” being the most popular & “Brownish Red”the least popular. At least this is what I have encountered in the trade for the past few years.)
The most common sources of rubies are Burma, Thailand, Madagascar and Africa.
The Value of Rubies.
The value of rubies come from the 4 Cs. (Colour, Carat, Clarity, Cut), their country of origin and treatment.
For rubies from Myanmar (Burma), they tend to cost much more then rubies from other localities.
Some reasons could include:
1. Burmese rubies, especially from the Mogok region have Vanadium in them. Vanadium gives the rubies a red “glow”, making them more attractive and desirable. Burmese Rubies contain less iron as compared to Thai ones, therefore they look more lively!
2. To bring rubies out of Myanmar is difficult. First you got to get a visa to get into the country, hope that the customs won’t have an issue with you bringing so much cash <$10,000 US. When you buy the rubies, you have to get an official reciept to bring it out of the country. Even with this official receipt, you might have problems with the customs.
3. The name Myanmar / Burma is a brand name. The Burmese are very proud of their rubies, any ruby that has the tag “Burmese”, you will notice that they will cost more than any other locality.
Heat Treatment – a bane or a boon?
Although natural unheated rubies cost much more than heated ones, this doesn’t mean heated stones are cheap. Normal heat treated rubies can command a hefty price tag, for example a 3ct pigeon blood ruby can cost at least $20,000 per carat easily. Heat treatment has metamorphosized ‘ugly’, ‘undesirable’ ruby rough to ‘beautiful’, ‘desirable’ ones. A once unattractive ruby that no one wants (i.e. $10/ct) to a more attractive ruby that people would pay $50 per carat for it. This is almost a 5 times increase in price! Doesn’t it sound like a good money making idea?
On the other hand, it makes beautiful rubies more available to people! Glassed filled, diffused rubies are being sold from $2 per carat onwards. They look decent and they come with a very attractive price tag!
But to take it to the extreme, this is where ‘cheating’, ‘misrepresentation’, etc. arise. Many gem dealers and jewellers are having difficulty disclosing these treatment to their customers, the result, the lost of trust, lost of business, etc. The key to keep our trade alive is ‘Disclosure’.
Some heating techniques include
1. Normal heating oxidising(oxygen) atmosphere (removal of blue colour, brown tones.) – Colour is permanent.
2. Surface diffusion, heat to 1600 – 1900 degrees celcius (makes colour even) – Colour is skin deep & can be polished off.
3. Bulk diffusion, heated in the presence of another material (example Beryllium) – Colour is permanent.
4. Glass filling of fractures, heat to 1300 – 1900 degrees celcius to fill up surface reaching cracks and cavities. Improves clarity but glass can be damaged through wear and tear, acids.
At Far East Gems & Jewellery, we do not sell Surface diffused, glass filled or bulk diffused gemstones.
In the next installment about rubies, we’ll discuss about the 4 Cs of rubies.
Continue reading
