THE QUALITY OF A DIAMOND
Diamond (from FR. brillant “brilliant, sparkling”) — a diamond, which by processing is given a special shape, maximally revealing its natural Shine. Diamonds are estimated by the system “4 C”: cut , clarity, color and carat (weight in carats), which allows you to determine how close the stone is to perfection. To confirm the authenticity of a diamond requires a certificate issued by one of the Gemological laboratory HRD, GIA or EGL.
WHAT DOES CARAT MEAN?
Along with clarity, colour, and cut, carat is one of the “4 C’s” when it comes to the evaluation of diamonds.
Carat (abbreviated Ct) is a way to describe the weight of either a single diamond or multiple diamonds when sold together. In the latter case, jewellers talk about Ct, or total weight in carats. One carat is equal to 200 milligrams (.2 grams). Note that carat refers to the weight of a diamond and not the size, which is a common confusion.
GRAINS, POINTS, AND CARATS
Because a carat is a fairly large unit of weight, gemologists have relied upon a more exact measurement system using what are called Points and Grains in addition to Carats. When buying diamonds, one can refer to any one of these units. One carat is equal to 100 points, so a 50 point diamond is the equivalent of .5 carats. A grain is equal to 25 points, or .25 carats. So, for example, a 6 grain diamond would be the equivalent of 6 x .25 = 1.50 carats, or 150 points.
WHAT DOES CARAT MEAN TO YOU?
Larger diamonds occur less frequently in nature than smaller diamonds. So, all things being equal, if you are selling diamonds, a larger diamond will fetch a higher price for you than a smaller diamond. In any case, you should leave the evaluation of your diamond to an experienced diamond office, whose expert gemologists will be able to determine the exact value based upon industry-standard measurements and criteria.
HOW DOES DIAMOND CUT AFFECT VALUE AND BEAUTY?
Three of the “4 C’s” involved in the evaluation of diamonds—carat, clarity, and colour—depend upon the natural chemical and/or structural composition of the diamond. But the fourth C, cut, involves human intervention.
Cut refers to the introduction of facets—or flat, geometric sides—by a master jeweller. However, “cut” also encompasses three other factors: symmetry, proportion, and polish. The cut of a diamond, when done correctly, brings out the stone’s natural brilliance and its ability to reflect light, which is an important consideration when buying diamonds.
THE BRILLIANT CUT
You are probably most familiar with the round “brilliant cut,” which is the most common type of cut employed by a jeweller. It results in an iconic pyramidal structure, with a crown (the top part of a diamond) and a pavilion (the lower part of a diamond) separated by the girdle, or middle part. The brilliant cut features 58 distinct facets, which work with each other to refract light within the stone such that the maximum amount of light is released through the top of the stone. Given Antwerp’s historic tradition of master jeweller and gemologists, it is no surprise that Antwerp diamonds are known for their exceptional cuts.
GETTING CLEAR ABOUT DIAMONDS CLARITY
One of the “4 C’s” of evaluating diamonds, clarity is a crucial component of any assessment of a diamond’s aesthetic and monetary value. Clarity refers to the ability to detect—via the naked eye or magnification—imperfections on both the surface of the diamond and in its internal structure. “Blemishes” refers to surface imperfections, while “inclusions” speaks to unique characteristics inside the diamond.
MORE ABOUT INCLUSIONS
When buying diamonds, it is essential that the buyer have an understanding of a diamond’s inclusions and how they relate to both its brilliance and its value. Inclusions are measured with a scale called the clarity scale. It ranges from LC (Loupe Clean or flawless, with “Loupe” referring to the jeweller’s small magnifying tool) to Pique 1-3 (with P1 being somewhat included or imperfect, and P3 being very included or imperfect).
As you might guess, less imperfections are more desirable, as imperfections impact the refraction of light and affect a diamond’s light output and sparkle. Diamonds nearer to LC are more valuable than diamonds nearer to P3, all other things being equal.
To determine where a diamond falls on the clarity scale, a gemologist examines the diamond at 10x magnification. Inclusions can range from crystal-like structures to pin points, feathering, and clouding. Those selling diamonds must be keenly aware of a diamond’s clarity grade, as this significantly impacts the possible sell price.
THE TRUTH ABOUT DIAMOND COLOUR
Colour is an essential part of any evaluation of diamonds, and particularly diamonds. In the case of diamonds, colour is exactly what we would expect — the visible hue of a diamond. But colour gradations can be very slight and subtle, and it takes a trained gemologist with magnifying equipment, existing master stones for comparison, and a controlled lighting environment to accurately grade the colour of a given diamond. These master stones are graded and recorded at the GIA diamond lab, using white light and proper procedures. These stones are then used as a reference point for comparison in the evaluation of the colour of your diamonds.
THE DIAMOND COLOUR SCALE
When buying diamonds or selling diamonds, you should obtain a color grade as part of a diamond’s official certification. Colour depends upon a diamond’s chemical composition and the structure
of its crystal lattice. Diamonds are graded on an alphabetic scale ranging from D (Colorless, or “White” diamonds) to Z (very yellow or brown).
“D” diamonds are generally more desirable than diamonds closer to “O-P,” due to the relative rarity of “D” diamonds in nature. The colour of a diamond also impacts the selection of accompanying jewellery; whiter diamonds look great with white gold or platinum, while yellower diamonds look a little better with yellow gold.
The following table shows the color grades from colorless to brown:
D – E : Blue-white colourless
F – G : Colourless
H : First white colour
I – J : Very slightly coloured brown or yellow
K – L : Slightly coloured brown or yellow
O – P – Q : yellowish or slightly brown – champagne
DIAMOND TYPES AND RARE DIAMONDS
Diamonds are divided into Type I and Type II (with various subcategories), based upon the presence or absence of nitrogen impurities. The type of diamond accounts for certain labels for diamonds which you may have heard of, such as the Cape Series and canary diamonds.
Diamonds falling outside of the “normal” colour range—those diamonds which exhibit more intense colors—are called fancy colour diamonds. These diamonds are quite rare, and in the evaluation of diamonds they are graded on a separate colour system.