Diamonds - 4C

Read the text if you want to learn more about diamonds…





Diamonds have always been considered to be among the most valuable things in the world. The fact that they are rare nature's creations with unique mechanical and optic characteristics, has made them quite special to people. Very often, you will find yourself in a situation where you are expected to explain why a diamond is more valuable that the other one. The value of a diamond is determined by its exact quality which is most easily defined by the 4Cs. To put it more precisely :

1. Carat (a metric unit of weight 1ct = 0.20g)
2. Collor
3. Clarity
4. Cut

Precision in defining 4Cs characteristics is very important as a part of marketing strategy, because people like to be fully informed about the products on which they are about to spend significant amounts of money, especially if they are as small as diamonds.
At the moment, several diamond quality grading standards are being used.
GIA ( the Gemological Institute of America) is the most applied one, both in trade and most famous gemological laboratories throughout the world.
CIBJO (Confederation Internationale de la Bijouterie, Joaillerie, Orfevrerie, des Diamants, Perles et Pierres) is an international association, supported by the representatives of 19 countries, whose diamond nomenclature was revised in 1986.
Although it is still too early for making such predictions, there is a good chance for it to become widely accepted.
In addition, there are IDC, RAL and Scan.D.N., but they are of less importance for us. In the scales supplementing the text,
old terms are given for comparison purposes.

Carat or weight is the term which has the same meaning in all standards : 1ct = 0.20g. A firmly held belief that an item costs more if it is bigger than others is common to all people. The only unusual thing is that the price of a gemstone grows progressively with the increase of its weight ( or size ). However, this becomes quite logical if you consider the fact that big diamond crystals are found less frequently in nature. For instance, a 1-carat gemstone costs a lot more than four 1/4 carat gemstones of the same quality. It has been widely accepted to measure diamonds in figures with two decimals. For example, a certificate can contain the information that a gemstone weighs 1.23 ct. The diamonds used in jewelry cannot be measured precisely. Therefore, the tolerance of +- 10% is allowed in weight measurement. The main purpose of this method is to measure a diamond's diameter and height, relate the measures to girdle thickness rating and read the weight of the cut in the scale.

Collor. People are most inclined to believe that only colourless diamonds exist. It is a wrong belief, because diamonds come in all rainbow colors. However, colourless or almost colourless diamonds have the greatest turnover. Diamonds with no hint of color are most expensive, with the exception of those of fancy colors, like blue, pink or red.
Grading is based on how much a diamond is far from being absolutely colourless. The closer is a diamond to having no color, the higher grading ratings and price it has. At the same time, there is a rule as far as fancy colors are concerned - the more intensive and clearer is the color, the higher price a diamond has. Actually, color is more noticeable if a diamond stone is bigger.
In other words, if we compare two diamond stones of "G" color, it is more pronounced in the case of a 1-carat gemstone than the 0.10 carat one. If a diamond has been used in a piece of jewelry of metallic color, it can disguise or emphasize its color.
This results in its less precise grading ratings in comparison to those of an unmounted one.Therefore, people often decide to spend their money on a bigger gemstone with lower color grading ratings , as soon as they realize how much a slight difference in color can influence the price. Fluorescence is a quite often diamond characteristic.
When exposed to ultraviolet light, some diamonds give off blue and more rarely green, yellow or red coloration.
Sometimes, this characteristic is quite distinct and therefore visible in the daylight. This kind of diamond stones used to be called "Blauweiss", "Blue white" or "Jager"and it was regarded exceptional for its color. Nowadays, fluorescence is easily noticed while exposing diamonds to the light of an ultra-violet lamp. Fluorescence is a characteristic which does not make diamonds more valuable - on the contrary, it reduces their price because it makes them look unclear and smeared.
The term "Blauweiss" is no longer in use and, in some countries, it is even forbidden in trading.

Clarity. The products of nature are never absolutely clean and perfect. Although they are rare, there are diamonds which do not show any interior inclusions or surface irregularities while being viewed by an expert under 10 times magnification. Such gemstones are called "Flowless" or "Loupe clean" and they are usually highly prized. At the other end of the scale, there are gemstones with too many inclusions which affect their integrity, durability and beauty. Diamonds with more easily or hardly seen inclusions, which do not have any negative effects on their beauty or durability, stand between these two extremes. What I am trying to point out here is that every gemstone with inclusions should not be immediately considered to be a bad one. They can sometimes be interesting and intriguing, helpful in identifying a gemstone, in specifying its "name and surname". At the same time, they are the most valid proof that a diamond stone is not a product of imitation. The old terms - "coal" or "ice" - are not in use anymore because they proved to be inadequate for marketing purposes, since they incited a feeling of resentment. It is more appropriate to say "light" or "dark" inclusion, or use the word "feather" for a small crack inside a diamond stone.
More recent nomenclatures are quite identical, which is illustrated by the comparative charts.

Cut.This is the only contribution to the beauty of diamonds made by a man. It affects other three Cs in an important way. A well-cut diamond can reduce a negative effect made by a low-graded color or hide a minor inclusion through nice fire. However, compromises between optimal cutting and maximum weight, which can be drawn out of an unprocessed crystal, are often made in the process of cutting. As you can probably guess, the main goal is to secure as bigger profit as possible. As a result, we often come in touch with diamond stones whose cut is far from being ideal. As far as this "C" is concerned, nomenclatures are also not compatible. Consequently, some are more rigorous than others.
And so, diamond stones with previous three "Cs" being equal and cuts of completely different quality are quite often sold at good price. This is where an expert's knowledge is most needed. It is very important to make a difference between a well and badly cut diamond before deciding what to buy, because prices are often similar.
In the case of this "C", it is necessary to make a difference between two things : style and cut .The term "style" refers to the shape of a diamond stone and the way facets are placed. When we say "cut", we refer to a diamond's proportions and final polish.

Scale application note:
according to the CIBJO standards, first two color gradings comprise two ratings
( for instance, Rare white + and Rare white) only in the case of 1/2 carat gemstones (more precisely, 0.47ct).
The same principle is applied to clarity.
For example, VS is divided into VS1 and VS2 only in the case of 0.47carat gemstones.

Andrejevic Kosta