Do you want to buy a diamond necklace or ring because you cannot resist the brilliance of our precious stones? Specialists at certification labs such as GIA, IGI and HRD examine the diamonds that we sell at BAUNAT closely, to verify whether they are a natural or synthetic diamond or even an imitation. But they analyse other qualities of the precious stones, such as the 4 C’s, that determine their value.
To examine the gem stones in depth, the experts use a number of special research instruments. What equipment do the specialists use, and what exactly do they use it for? Take a look into the toolbox of the diamond expert at GIA ...
- With a visual spectrophotometer, a specialist examines how, for example, the colour of a diamond is created.
- An infrared spectrophotometer allows them to identify the diamond type, and to distinguish whether or not the diamond has been treated.
- Thanks to a Raman spectrometer or an X-ray diffractometer, an expert knows exactly what material they are examining.
- Research into the X-ray fluorescence of a gemstone gives a quick insight into its chemical composition. Its exact ratio is revealed by an LA-ICP mass spectrometer. Both methods allow them to make a distinction between natural, synthetic and imitation diamonds.
- With the photo-microscope, an expert takes photographs of inclusions and other aspects of gemstones, magnified by a hundred times.
- The DiamondView instrument from De Beers distinguishes synthetic from natural diamonds.
With the initial set of tools we discuss here, the experts do not even have to touch a precious stone to examine it. He or she simply illuminates it with light, and then studies how the light’s composition is changed by its interaction with the stone.
What is a visual spectrophotometer used for?
A gemstone can partially absorb visible light. To study that phenomenon, the specialists use a visual spectrophotometer. This device shines a narrow ray of visible light through the stone: from light with the lowest frequency (longest wavelength) that we as people can still see as red light, to light with the highest frequency (shortest wavelength), which we see as violet light. Light with certain frequencies (and certain colours), is absorbed less, and thus escapes from the diamond. This escaping light determines which colour the diamond appears to be.
The spectrophotometer captures the emerging light. The end result is a graph that reflects either the radiated or the absorbed light per wavelength. By studying that graph, the expert discovers among others, where the colour of a diamond originates from.
What is an infrared spectrophotometer for?
A gemstone also absorbs infrared light. We cannot perceive that light with the naked eye, we feel it as heat instead. The stone can absorb, transmit or reflect the infrared light.
In order to map this phenomenon, for example, the expert exposes a diamond to an infrared spectrophotometer. It emits light with different infrared frequencies or wavelengths. This is how the researcher can find out which type of diamond he or she is analysing. A Type I diamond gets its colour from chemical impurities, whilst a Type II diamond get its colour from structural deviations in the crystal form. Read more about these diamond types in a previous blog post.
At the same time the specialist discovers whether a coloured gemstone has been treated with substances such as resin and oil. This malicious technique is used to improve the gloss. But the research method with infrared light also helps to, for example, discover diamonds that have been irradiated to improve their colour.
What do the diamond experts investigate with a Raman spectrometer?
With a Raman-spectrometer the specialist shines a laser light of almost one single colour onto a certain material. Most of the light does not change colour, or change wavelength. But a small part of the light wavelength does change. The exact extent of this varies from molecule to molecule. According to the strength of the effect, molecules can be identified. In other words …
By comparing the light emitted with values of other materials that were previously examined with a Raman spectrometer, the expert can find out perfectly which material they are examining. For example, a diamond.
And what does an X-ray diffractometer do?
A mouthful, isn’t it? With this device, the expert examines the crystal structure of a precious stone. For this purpose, a sample of it is ground into powder (if this is possible, of course) and then exposed to X-rays. These rays are broken or bent at certain angles, depending on the atomic structure of the crystal.
By comparing the pattern by which the X-rays differ with patterns that were previously determined by different types of precious stones, the specialist knows exactly which type of gemstone lies in front of them and ends up in your diamond necklace later on. For this the expert has to sacrifice a small sample of the stone.
Why does an expert also investigate X-ray fluorescence?
Again not a simple term, we know. But the science behind it allows an expert to very quickly discover the chemical elements of a gemstone, albeit without knowing the exact proportions. And that without the researcher having to sacrifice part of the stone.
As with the diffractometer above, the expert irradiates a gemstone with X-rays. The material itself then emits other X-rays, which are typical of the chemical elements of which the diamond is composed. We call this phenomenon X-ray fluorescence. This is a variation on ordinary fluorescence, a phenomenon where a substance emits light when it is illuminated. An example of this? Just think of the fluorescent vest in your car.
Another spectrometer, to learn: LA-ICP-MS
Want to know how a specialist knows the proportions of chemical elements in a gemstone? He or she can determine this with an LA-ICP mass spectrometer. This device focuses a laser beam on a sample of the precious stone, removing small particles. These are then taken by a running gas to a so-called plasma torch.
The torch heats these particles in such a way that they completely disintegrate into their individual atoms. This allows the researcher to accurately map every quantity of each chemical element of the gemstone, down to the lowest concentrations. An amazing result, and only a very limited amount of diamond is lost.
Both the research of the X-ray fluorescence and the LA-ICP mass spectrometer allow you to check whether the diamond that ends up in your diamond necklace or ring, is natural or synthetic, or if it has been treated.
Instruments for in-depth imaging
A final series of devices provides the expert with extreme close-up photos of certain characteristics or inclusions in a gemstone. This allows the scientist to discover how the material has formed and, in certain cases, even where the stone comes from.
With a photo-microscope for example, photographs taken of inclusions and other aspects of gemstones are enlarged one hundred times.
In addition, the diamond producer De Beers developed the DiamondView-instrument, a device to distinguish synthetic from natural diamonds. This device shines ultraviolet light on the gemstone, after which it fluoresces.
Depending on whether the diamond was created by the forces of mother nature or in the lab, the colour of the fluorescence and its pattern differ. With a synthetic diamond there is no phosphorescence, unlike its natural counterpart. Phosphorescence is a phenomenon in which the gemstone, after being exposed to light, shortly lights up afterwards itself.
Some more basic instruments
In addition to high-tech devices as discussed above, diamond specialists also use some 'simpler' devices. For example, a magnifying glass or a microscope, but also a polariscope. With the latter device the specialist can distinguish gems by how the light is broken, either once or twice. The first type includes diamonds. Emerald, ruby and sapphire are part of the second category.
How can you guarantee the quality of your diamond necklace?
With such instruments, institutions such as GIA succeed in accurately and reliably determining the quality of precious stones. They can also make the distinction between synthetic and natural diamonds, or bring treated diamonds to light.
Because BAUNAT only sells diamonds that are certified by GIA, IGI and HRD, you can always be certain of the quality when you buy a diamond necklace or ring at BAUNAT. We also guarantee that we only purchase gems from reputable producers.
With all this certainty, are you even more convinced that you want to buy the diamond necklace or ring that you have in mind? Shop immediately in our collection of necklaces and rings or contact our experts for additional advice.