General Information About Diamonds
The quality of a brilliant is defined depending on the 4C features: Carat, Clarity, Colour and Cut. These characteristic features do not only help to sort out the stones due to its quality, it is also extremely useful in identifying the brilliants, since every brilliant is unique.
Carat is the weight measure of a brilliant. One carat is equal to 0.2 grams. A carat is also subdivided into hundred equal units, called points. For example, a stone of 1.50 carat means 1 carat and 50 points. HRD has highly accurate scales reading up to 1/100,000 of a gram.
As soon as the brilliants arrive at the reception desk, they are weighted. The recorded weight is then converted into carats and rounded off to the nearest digit. On the receipt of purchasing and return notes, the weight of the brilliant is shown up to five decimals. This accurate recording of the weight of the stone is crucially important for the identification of it. On the certificate and/or ID report, the weight is recorded up to two decimals. For example: 1.50 ct = 1 carat and 50 points.
The clarity or purity of a brilliant is determined by the number, size, brightness and location of the internal and external characteristics, important structure phenomena and transparency. Basically, the clarity is mainly set by the inclusions within the stone. The fewer inclusions or structure phenomena a stone displays, the higher the quality of the brilliant.
Over 90% of all diamonds are mainly yellowish in colour. The intensity of the yellow varies from almost colourless, much preferable, to definite yellow. The colourless stones are much more valuable than the yellowish ones. Besides, the brilliants can have orange, brown, pink, green and blue colours. These colourful diamonds could be extremely valuable.
The quality of the cut is determined by the proportions and finish grade of a brilliant. A good finish grade shows how dexterous is the workmanship of the brilliant. This term also refers the symmetry of the surfaces and their overall finish. The best cut brilliants also have the right proportions between the different parts of the brilliant.
When the proportions are not optimal, the fire and the glitter of the brilliant are negatively affected and undesirable visual effects might occur. Apart from the most popular cut amongst the other known cuts is the ‘round cut’, and splendid ‘fancy cut’ brilliants could be found as well.
From Carbon to Diamond
Diamond has several unique and extreme properties. It is the hardest, the least compressible and the best thermal conductor among all known materials. Moreover it is chemically inert to most acids and alkalis. These exceptional properties make diamond valuable both intrinsically as a gem, for usage in industrial applications, and as a tool for scientists concerned with unraveling Earth processes. Although diamond is decidedly rare, it actually consists of one of the most common building blocks of the material world: carbon.
Diamond is made up solely of carbon atoms, which form short, stable and strong bonds among them. What makes diamond so hard is its three-dimensional crystalline structure of regularly arranged carbon atoms.
A symbol of wealth, purity and love, a diamond leaves no one unmoved.
In India, the diamond has traditionally enjoyed great fame as a talisman, thanks to its exceptional hardness and other properties. It was a symbol of courage and virility, qualities that were considered exclusively male. It is said that when Alexander the Great reached the Valley of Diamonds he saw that the valley floor was studded with diamonds guarded by giant snakes with deadly gazes. But Alexander had a plan and cheated the snakes out of their diamonds.
Its unique properties, conspicuous even in a barely worked stone, have shrouded the diamond in a veil of symbolism, mysticism and mystery. And from mystery to superstition is but a small step. The Romans, for example, believed that the stone would protect them against poison and plague. There were those who believed that insomnia, enchantment, fear and pain could all be overcome with the help of a diamond. As a symbol of the love between partners, diamond was also called “the stone of reconciliation.” Romantics would have it that the love darts of the Roman god Cupid were made of diamond. Less romantic was Catherine de Medici’s habit of getting rid of her adversaries with poisonous ‘inheritance powder’ made from finely ground diamonds.
Today, the diamond has grown to become the symbol that defines important emotional events such as an engagement, birth or anniversary, or to immortalize personal achievements.
Diamond is the stable form of carbon at high pressure and temperature conditions. At a temperature of 1325°C, a pressure of 50000 kg/cm2 is required to grow diamond. This extreme pressure corresponds to the weight of the Eiffel tower (9441 tons) on your hand. Without this pressure, graphite instead of diamond forms.
The play of light in a diamond
Aside from its extreme hardness, the diamond is characterized by a number of distinctive properties: Almost all diamonds contain foreign atoms. The most commonly occurring example of this is nitrogen, which is responsible for a yellow color tinge that is visible in many stones. A perfectly pure diamond is completely colorless and non-fluorescent.
Transparency: : The transparency of a diamond varies from completely clear to completely opaque. Only the clear stones are used in jewelry. Other diamonds are used for various, although usually industrial purposes. A stone that does not sparkle after it has been cut and polished is known as a “dead” stone.
Clarity : Pure diamonds are extremely rare. Almost all rough diamonds contain impurities or “inclusions,” which are traces of non-diamond materials that were ‘trapped’ in the mineral during the stone’s formation. Many inclusions are removed during the cleaving, sawing, cutting and polishing of the diamond.
Brilliance : In general, rough diamond is not particularly attractive; it barely sparkles. The diamond only achieves its characteristic, stunning brilliance after it has been polished. The diamond’s unusual attractiveness and play of color is due to its reflectivity and exceptionally high refractive index, by which the light is optimally “broken”. The result is a dispersion of the white light into all the colors of the rainbow. Of course, all the facets of a polished diamond have to be oriented properly for this effect to be obtained. Only then does the stone come to life.
Diamond receives the highest possible score of 10 on the Mohs scale, which measures hardness in gemstones. This means that diamond scratches every other material without being scratched itself. No acid or base (alkali) can corrode diamond.
Diamond repels water but attracts fat. For this reason, you should avoid touching a polished diamond with your fingers. Diamond is a good conductor of heat. Thus, when it is not in contact with a source of heat, it always feels cold in itself.
A long journey
Scientists believe that the Earth is more than 4.5 billion years old while the oldest modern humans are just less than 160,000 years old. Having this time span in mind it is interesting to note that the oldest diamonds we know date from 3 billion years ago. In most cases, the diamonds are stored deep in the earth for considerable times, sometimes for billions of years, before reaching the Earth’s surface.
Academics agree that gem diamonds are formed deep in the Earth, and more in particular at depths of about 150 to 200 kilometers below the surface. Thanks to volcanic activity, the precious mineral is brought to daylight. The diamond-containing magma that crystallizes by cooling is known as kimberlite or lamproite. An important diamond discovery includes the presence of about 1 carat of diamond in a ton of the mining ore kimberlite or lamproite.