Might be a certificate called the ID of a diamond, which a great significance in its purchase because it represents a proof of the identity and the value of a diamond. For this reason is called the certificate like the fifth C – in addition to the four CS colour (color), clarity (purity), Carat (karat) and cut (cut).
It is very important to ensure that the certificate (called also expertise) was issued by a recognised Gemmological Institute. This is particularly renowned in this area Gemological Institute of America (GIA), which applies strict standards for the issuance of certificates.
But what information does such a document and what should I know to understand it? To answer these questions, the structure and the individual subitems of a GIA to discusses the following certificate for diamonds.
The authority of the GIA in the certification of diamonds
There are several institutions that make certificates for diamonds and differ considerably from each other. So, for example, the EGL (European Gemological Laboratory) for the individual characteristics of quality is more lenient than the GIA or the IGI (international Gemological Institute). This can the buyer incorrectly the impression, that the diamonds certified by the EGL had a lower rate than those with a GIA report – this is not true however.
The GIA is the world’s largest and oldest independent gem laboratory, whose Expertisen are characterized by their reliability. The institution is also important because the method developed by you, to determine the quality of diamonds based on the four cs, has been adopted as international standard.
The information on a GIA certificate for diamonds
GIA certificate number, date, laser inscription
The date of issue is imprinted on every diamond certificate of the GIA. The new is the expertise, the better.
All certificates of the GIA get associated with a unique number, under which they can be found in the extensive database of the Gemmological Institute. These can be inscribed on request with the help of laser beams on the girdle, the belt of the diamond of. This increases the security of diamond and certificate really belong together.
The shape of the diamond and its mass on a GIA certificate
Under the point shape and cutting style specifies what form does the girdle and in what manner the facets are arranged. It’s a diamond brilliant cut, so the notice of round brilliant; certificate can be found on the GIA When a diamond oval cut, however, oval brilliant. The square princess cut, which has a different facet of the brilliant cut, called a Rectangular Modified Brilliant .
The dimensions (measurements) are recorded differently depending on whether it is a brilliant or a diamond in the Fancy Cut .
Rarely a gem has a perfectly round shape, which is why two values for the diameter is located on a GIA certificate, a maximum and a minimum (minimum diameter maximum diameter x depth). The less these two differ, the more even the diamond is shaped.
Diamonds, fancy cuts given the mass according to the system length x width x depth .
The grading results with regard to the four CS on a GIA certificate
The size of a diamond is important, of course what affects its value. She is (1 Carat equals 0.2 grams) specified in Carat (Carat) and rounded to two places after the decimal point. The price per carat increases strongly with the size of a diamond and that a Zweikaräters is much higher than the double of an Einkaräters.
Next up is the color level (color grade) based on the rating scale developed by the GIA of D (high rare white +) judged to Z (yellow). This is very difficult because the individual shades differ only very slightly from each other and to see almost no difference with the naked eye. For this reason, the color at the GIA from different appraisers is independently assessed and only finally defined, if they have a matching result. The light source and the background have a great influence on the perception of color, which is why diamonds are graduating from the GIA under standard viewing conditions.
The purity (clarity) of a diamond is determined in tenfold magnification under a microscope. Here one finds specifically the GIA scale developed application from FL flawless (flawless) up to I3, very large inclusions (inclusions 3) enough. Rarely, a diamond is flawless; mostly, he is marred by impurities occur either in the form of inclusions or errors in the surface structure. The classification of purity is their size, number and positioning in the diamond.
The quality of the cut (cut) is highly relevant. It is specified by the GIA only for diamonds brilliant cut, located within the gamut from D to Z, so for colored diamonds (Fancy Diamonds), nor for those in different cut forms (Fancy Cuts).
A fiery and sparkling appearance is a sign of a good finishing touch. In addition, the proportioning of the diamonds plays an important role. Therefore the Pavilion (lower part) should be either too shallow or too deep, since otherwise the incoming light rays are reflected not so nice and dark spots in the gem. The cut version also the durability of a diamond affects: the girdle should be not too thin, because she will otherwise prone to damage, but also not too thick because it negatively affects the brilliance.
The GIA rating scale ranges at the cut from excellent to poor.
The finish line of a diamond – evaluation of polishing and the symmetry by the GIA
In addition to the four cs, there are other factors that affect the value of a diamond. So certificate is taken into account on a GIA the finish, which is composed of the Polish and symmetry. The facets of a diamond have a smooth and even surface, this is a sign of a high-quality polishing.
Under the point symmetry is checked whether the outline of the gemstone has a perfect geometric shape, and continue to, whether the facets are evenly shaped and symmetrically placed. Both criteria be assessed, such as the cut, using a scale from excellent to poor , and they are responsible for the fire of a diamond.
The GIA certificate – the fluorescence of a diamond and additional information
A GIA certificate contains a note about it, is whether the diamonds to observe fluorescence. This phenomenon occurs, the gemstone under UV-radiation in the blue – an effect that negative exerts on its value, appreciated by some but is lit.
Under the point comments more characteristics of the diamond are – listed if available – otherwise not certificate are noted in the GIA.
If you have engraved inscriptions on the diamond, so these are listed.
The diagrams invalidate certificate – GIA, rating scales and safety precautions
A GIA certificate is supplemented by diagrams, which show the faceting of the top and bottom of the diamond, and on which schematically size, position, and type of any impurities are marked. The different symbols used are explained in a legend.
In addition, a sketch is shown to illustrate that contains percentages to the proportions and comments to the thickness of the girdle and the size of the Culet (the facets at the bottom tip of the diamond).
Each certificate by the GIA provides the rating scales for colour, purity and grinding, as well as a GIA hologram, which ensures the authenticity of the document.
Here you can watch a GIA certificate: issued by the GIA expertise as PDF.
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