Diamonds have been highly prized for centuries and are widely recognised for their exceptional beauty, durability, and rarity. They are typically colourless but can also come in a range of hues including yellow, brown, pink, blue, and green, among others. The value of a diamond is determined by several factors, including its size, colour, clarity, and cut.

Weight of diamonds is measured in carats, with one carat being equivalent to 0.2 grams. The colour of diamonds ranges from colourless to yellow and brown, while clarity refers to the amount of inclusions or internal characteristics present in a diamond. The less inclusions a diamond has, the higher its clarity. Cut refers to the shape and style of the diamond's faceting, and affects its brilliance and beauty.

Diamonds have been prized for their beauty and durability for thousands of years. Today, they are used in jewellery, timepieces, and cutting tools. The diamond industry is highly regulated and based on certification and ethical business practices.

DIAMOND FACETS:

The facets of a diamond are flat surfaces cut into the gem that reflect light and produce its characteristic brightness and sparkle.

The most important facets include the table, crown, girdle, pavilion, and culet. Diamond cutting is a complex and careful process that requires skill and precision to maximize the gem's beauty.

One of the most important facets of a diamond is the Table, which is the flat top surface of the gem. The table is the first part of the diamond that comes into contact with light, and is primarily responsible for reflecting light back to the observer. The table must be perfectly centred and symmetrical to maximize the amount of light that enters the diamond and to produce optimal brilliance.

Another important facet is the Crown, which is the upper section of the diamond located between the table and the girdle. The crown is composed of several facets, including the main facets and the secondary facets, which direct light towards the table and produce the characteristic sparkle of the gem.

The Girdle is the part of the diamond that connects the crown with the pavilion, and may also have several facets that reflect light towards the crown and table. The thickness of the girdle is also important, as it determines the amount of light that is reflected from the crown towards the table.

The Pavilion is the lower section of the diamond, and is composed of several facets that reflect light towards the crown. The angle and symmetry of these facets are crucial for maximizing the diamond's brightness and fire. It is also important that the depth of the pavilion is appropriate, as this determines the proportion between the girdle and the crown, which affects the quality of the diamond's brightness.

Finally, the Culet is the flat surface at the bottom of the diamond, which is usually left un-faceted. The culet can be polished to varying degrees of roughness to improve the stability of the diamond in its setting and to facilitate cleaning and maintenance.

A Round Brilliant cut diamond for example, has a total of 57 facets (58 if the culet is present), with 33 in the crown and 24 in the pavilion. The girdle may or may not be faceted or polished.

4 C's OF DIAMOND QUALITY:

The Gemological Institute of America (G.I.A.) is a leading organization in the evaluation of diamonds and has developed a set of criteria for diamond classification known as the "4C's". These 4C's are: cut, clarity, color and carat weight. Each of these factors is essential in determining the quality and value of a diamond:

Cut refers to how the diamond is cut and polished, affecting its brightness, fire, and light sparkle. A good cut maximizes these characteristics and produces a more attractive-looking diamond. Cut can also influence the appearance of a diamond's size.

Clarity refers to the presence or absence of internal inclusions or surface blemishes  in the diamond. Diamonds with fewer inclusions are more valuable because they are rarer and harder to find. GIA has a clarity grading system ranging from "flawless" to "included" that determines the diamond's purity level.

Color refers to the presence or absence of colour in the diamond. Diamonds are graded on a color scale ranging from D (colourless) to Z (yellow or brown diamonds). Diamonds with less colour are more valuable because they are rarer and considered of higher quality.

Carat weight refers to the weight of the diamond, measured in carats. One carat is equal to 0.2 grams. Larger diamonds are rarer, making them more valuable, as long as they meet the criteria for cut, clarity, and colour.

CUT:

Diamonds are known for their ability to transmit light and shine intensely. We often think of a diamond's cut as its shape (round, heart, oval, marquise, pear), but what cut really means is how well a diamond's facets interact with light. It takes skilled craftsmanship and precision work to shape a stone so that its proportions, symmetry, and polish provide the magnificent return of light that's only possible in a diamond.

Achieving the best cut for a diamond reveals  the beauty and final value of the stone. Of the four factors used to evaluate a diamond (the 4C's), cut is the most complex and technically difficult to analyze.

The proportions in a diamond's cut allow the evaluation of the best cut, studying how successfully a diamond interacts with light to create desirable visual effects, such as:

  • Brilliance: the white light both internally and externally reflected by a diamond.
  • Fire: the dispersion of white light into all the colors of the rainbow.
  • Scintillation: the amount of sparkle produced by a diamond and the pattern of bright and dark areas caused by reflections within the diamond.

CLARITY:

Natural diamonds are the result of carbon exposed to extremely intense heat and pressure deep within the earth. This process can result in a variety of internal characteristics called "inclusions" and external characteristics called "blemishes".

Evaluating a diamond's clarity involves determining the number, size, relief, nature, and position of these characteristics and how they can affect the overall appearance of the stone. If one tries to determine the best clarity for a diamond, it should be remembered that no diamond is perfectly pure. But the closer it is to purity, the better its clarity will be.

The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades:

  • Flawless (FL): No inclusions or visible imperfections under 10x magnification.
  • Internally Flawless (IF): No visible inclusions under 10x magnification.
  • Very, Very Slightly Included (VVS1 and VVS2): Inclusions are so slight that they are difficult to see for a trained evaluator under 10x magnification.
  • Very Slightly Included (VS1 and VS2): Inclusions are visible with effort under 10x magnification, but can be characterized as minor.
  • Slightly Included (SI1 and SI2): Inclusions are visible under 10x magnification.
  • Included (I1, I2, and I3): Inclusions are obvious under 10x magnification, which can affect transparency and brilliance.

COLOUR (COLOR):

The colour of diamonds has been considered important since ancient times. The first denominations were given based on the types of diamonds commonly found in deposits, using the name of some mines to define different grades of colour: Jager (after the Jagersfontein mine), River (from deposits found in riverbeds), Wesselton, Kimberley, Premier, etc.

To distinguish South African yellow diamonds from similar Brazilian ones and to highlight their African origin, the term "Cape" was used after the South African city of Cape Town. Some of these historical names remain in professional language, and are even used as grades in some scales, but others were omitted in modern nomenclature mainly due to their ambiguity and the inappropriate commercial use that was made of them.

Currently, there are four main scales used to designate diamond colour grades in the colourless series, each belonging to an internationally recognised association linked in some way to gemological education or gemstone trade: GIA (Gemological Institute of America), HRD (International Diamond Council), IGI (International Gemological Institute) and CIJBO (International Confederation of Jewellery, Silverware, Diamonds, Pearls, and Stones).


Color Scale
GIAHRD/IGI/CIJBO
D (colourless)DD
E (almost colourless)EE
F (almost colourless)FF
G (almost colourless)GG
H (slightly tinted white)HH
I (slightly tinted white)II (almost colourless)
J (slightly tinted white)JJ (almost colourless)
K-M (slightly yellow or brown)K-MK (slightly yellow)
N-R (yellow or brown)N-RN-Z (yellow or brown)
S-Z (yellow or brown)-N-Z (yellow or brown)

WEIGHT (CARAT WEIGHT):

The carat weight of a diamond measures how much a diamond weighs. One metric carat is defined as 200 milligrams. Each carat is subdivided into 100 'points'. This allows for very precise measurements to the hundredth decimal place. A jeweller can describe the weight of a diamond less than one carat in size only by its 'points'. For example, a jeweller can refer to a diamond that weighs 0.25 carats as 'twenty-five points'. Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as 'one point zero eight carats'.

If all else is equal, the price of a diamond increases with the carat weight because larger diamonds are rarer and more desirable. However, two diamonds of equal carat weight can have very different values (and prices) depending on the other three factors of the 4Cs of diamonds: Colour, Clarity, and Cut.

Historical facts:

How did the carat system start? The carat weight began with the carob seed, when the first gemstone traders used small, uniform seeds as counterweights on their balance scales. Nowadays, the carat has the same weight in milligrams all over the world.

Carat-millimetre relationship:

The weight of a diamond is measured in carats, while the size is measured in millimetres. As the weight of the diamond increases, so does its size, but not in a proportional way.

For example, a round diamond weighing 1 carat usually has a diameter of around 6.5 millimetres. However, a round diamond weighing 2 carats will not have a diameter of 13 millimetres, but will be around 8.2 millimetres. This is because the size of the diamond is affected by other factors besides weight, such as shape, depth, and table. Therefore, it is important to take both weight and millimetre measurements into account when evaluating the quality of a diamond.

DIAMOND CUTS:

The cut refers to the way a diamond has been cut and how the facets have been arranged on its surface to allow light to pass through it and reflect inside.

The most common cut is the round cut, which is used in over 75% of diamonds. The Round or Brilliant cut has been designed to maximize the amount of light that enters the diamond and reflects inside, giving it exceptional brightness and fire.

However, there are many other diamond cuts that can be equally beautiful and unique. The Princess cut, for example, has a square appearance and can be an excellent choice for those seeking a more modern diamond. The Cushion cut is also a popular option, with a soft, rounded appearance often associated with antique diamonds. Other diamond cuts include the Marquise cut, which has a long, slim appearance with two pointed ends, and the Emerald cut, which has flat, rectangular facets that create an elegant and sophisticated appearance. Also other popular cuts are the Pear cut or the Heart cut.

Each diamond cut has its own charm and may be suitable for different personal preferences and jewelry styles. When evaluating the quality of a diamond, it is important to consider both the cut and the other 4 Cs characteristics: color, clarity, and carat weight.

FANCY DIAMONDS:

While many people think of diamonds as bright and colourless gems, some rare diamonds have magnificent colours. These coloured diamonds are called Fancy Diamonds. Occasionally, nature becomes creative and produces diamonds with almost magical colours: blue, pink, deep yellows, and even green tones. And sometimes humans intervene to enhance or create the colour. Fancy diamonds are highly valued, but even more so if their colour is the result of natural processes.

Blue diamonds are one of the rarest fancy diamond colours, making this particular stone very special. GIA, for example, evaluates these fancy diamonds, less for their brilliance or fire, and more for the intensity and tone of the colour. And evaluation is essential. Many diamond retailers will have a "GIA Colored Diamond Grading Report" accompanying the diamond. If the stone does not have one, we recommend that the stone be graded so the buyer knows its colour grade and whether the colour is natural or the result of treatment.