A diamond is crystallised carbon. A diamond is hard. A diamond is forever. More than an advertisement slogan, it is a magic blend of the emotional, the physical and the spiritual. The foundation of the demand for natural diamond is based on its symbolic rather than utilitarian value.
Buying diamond can be a challenging experience for many people. However, if you familiarise yourself with the stone and spend time observing, listening and asking the right questions, you will then know what you need as well as be able to buy stones at the right price. Nowadays, however, it is not enough knowing the 4C's - a diamond's colour, clarity, cut and carat. Increasingly, you need to be aware of and, hopefully, be able to differentiate between natural diamonds and 'non-natural' diamonds. Amongst the latter, synthetic diamonds are of particular significance nowadays.
Natural vs "Non-natural"Due to their great popularity, and hence the high potential profits involved, diamonds can be the subject of enhancement, synthesis and simulation. Enhancement or treatment can be applied to natural diamonds to improve colour or clarity. Synthetic diamonds, on the other hand, are made in a laboratory, and have the same physical, chemical and optical properties as their natural counterpart. Simulants only resemble natural diamond in appearance. However, the composition of the most widely used diamond simulants, such as synthetic Moissanite and cubic zirconia, is very different from that of natural diamond.
Synthetic DiamondsSynthetic diamonds have been in the market since the late 1950s. Near-colourless synthetic diamonds, produced by Russian companies, were marketed to the gem trade in limited quantity toward the late '90s. Most synthetic diamonds are small and coloured. They are available in a range of sizes (less than 3cts), shapes and colours, especially yellow, yellow green, red, blue and pink. Colourless to near colourless synthetic diamonds are rare and more difficult to produce commercially.
Gem quality synthetic diamonds have been produced from Japan, the United States, South Africa and Russia for some time. Suppliers include Chatham Inc, Lucent Diamonds, Morion Company and First Diamond Group. Lately, Gemesis Corporation, a Florida-based company, has been producing synthetic diamonds with the help of Russian scientists and has begun branding its product as 'cultured diamond'. The company produces high quality cut cultured diamonds of up to 2.0cts in fancy colours, and plans to introduce synthetic blue rough diamonds some time this year. Apollo Diamond, a research company based in Boston, has succeeded in growing single-crystal diamond using chemical vapour deposition (CVD). The so-called cultured diamonds will be fully disclosed by the manufacturers. In fact, jewellery industry regulation requires that a synthetic diamond be always disclosed as such. The US Federal Trade Commission specifically requires that the word 'diamond' is accompanied by 'laboratory-grown', 'synthetic' or some other word or phrase of like meaning, so as to clearly disclose that it is not a natural diamond.
Telling the differenceWith so many types of diamonds and simulants on the market, how is one to avoid being shortchanged? My first advice is always to patronise a trustworthy jeweller. Such a jeweller provides proper disclosure, knowledge, professionalism, and a willingness to give you any information on request. In the absence of this, a vast majority of enhancements, synthetics and simulants are identifiable by standard gemological methods. Magnification, crossed polarisation filters and luminescence are important testing techniques. Under magnification and crossed polarisation filters, natural diamonds often show banded, crosshatched or mottled strain patterns and bright interference colours, while synthetic diamonds may display colour unevenness, graining, magnetic metallic inclusions, uneven fluorescence, and subdued cross-like black and grey patterns.
A simple way to get an indication of synthetic diamonds is the use of ultra-violet light. UV light gives an indication of the growth history of natural diamonds, which is completely different from that of synthetic diamonds. A natural diamond often fluoresces blue to long-wave UV radiation, and this fluorescence is usually evenly distributed, while synthetic diamonds typically fluoresce yellow to yellowish green to both long-wave UV radiation and short-wave UV radiation. A Russian synthetic stone often exhibits a green cross at the centre of its table when exposed to UV light. Near colourless synthetic diamonds often show phosphorescence.
And unless in cases of outright fraud, you can tell the difference by price. Synthetics and simulants are generally much lower-priced than natural diamond. Thus, do pay attention if you find that there is a significant variance between the price of "diamonds" of similar size and quality. As with everything else in life, you usually get what you pay for, not more. Diamond is the gem with the most standardised and comprehensive grading system. As such, many diamonds, especially the larger sizes, usually come with gemological certificates. If not, it could be worth sending such merchandise to a certified laboratory for authentication and certification. And for those of you who will consider buying a diamond simulant or synthetic diamond for various reasons, here's a thought: while simulated and synthetic diamonds are legitimate products, nothing beats owning the real thing!
Synthetic MoissaniteSynthetic Moissanite is an important simulant of diamond. Named after Dr Henri Moissan, the French scientist, it is produced in a laboratory. Near-colourless synthetic Moissanite, created by Charles & Colvard Ltd in the US, has been commercially viable since 1997. Because of its very similar thermal properties to diamond, synthetic Moissanite reads as diamond on most diamond testers. However, it has a number of properties that easily distinguish it from diamond. Synthetic diamond is double refractive, shows a doubling of the facet junctions under 10x magnification. Its specific gravity (3.21) is different to diamond (3.52). It is usually green in colour, or pale yellow to near colourless. The colour is usually below H. With caution, if you heat synthetic moissanite on a hotplate, it turns yellow. Synthetic moissanite costs about one-tenth of the price of diamond of similar size and quality. You can also differentiate Moissanite from natural diamond using a 10x loupe, based on the double images of the former's back facets.
(via Bangkok Post, Friday August 01, 2008): A stolen stone, which the owner claimed was a 2,100-carat uncut diamond valued at 315 million baht has been found to be a fake worth just a few hundred baht. According to Somchai Pornjindarak, president of the Thai Gem and Jewellery Traders Association, said the stolen item was not a diamond, but merely a cubic zirconia, or artificial diamond.
