The Four C's

1 - Cut

Cut fuels the diamonds fire, sparkle and brilliance.

Of all the 4’c the cut has the greatest effect on a diamonds beauty. A sad fact is, 75% of all rounds and 88% of other shapes are poorly proportioned to contain carat weight rather than to maximize sparkle.

This is the same diamond
Isn't it remarkable to see the difference in sparkle after it has been re-cut.

The Diamonds Anatomy

Proportion refers to the angles and relative measurements of a polished diamond. More than any other feature, proportions determine a diamond’s optical properties. Studies have shown that table size, crown angle, and pavilion depth have a dramatic effect on a diamond’s appearance. Symmetry is a grading term for the exactness of shape and placement of facets. Variations in symmetry include off-centre culets and tables, poor facet alignment, misshapen facets, out-of-round girdles, and wavy girdles.

Diamonds Shapes

Diamonds are cut in many varied and exciting shapes. The shape of a diamond should not be confused with its cut. Shape refers to the basic form of the diamond: oval or pear shaped, for instance. Cut or proportions, on the other hand, refer to the ability of each of these shapes to reflect light. When it comes to shape, it simply comes down to personal preferences. The right shape for you is really the one whose appearance you prefer. Shape can be a statement of who you are; like other areas of fashion, shape reflects your individuality and personality.

The round brilliant cut diamond is the most researched diamond shape available. Much work has gone into cutting calculations and techniques over the last 100 years in order to optimize the fire and brilliance in a round diamond. It also gives a greater flexibility in balancing grades of colour and clarify while still obtaining the fire and brilliance required.

Traditionally square or rectangular in shape with pointed corners, this is the most popular non-round shape and a favourite for engagement rings.

The pavilion of the emerald differentiates it from other shapes. This is cut with rectangular facets to create a unique optical appearance. Its larger, open table highlights the clarity of the diamond.

This shape has a wonderful brilliance similar to the round diamond. It is popular in rings as the length can accentuate the slenderness and length of the finger.

Like the oval, this shape makes the finger appear long and slender. It is also one which can maximise carat weight, making the diamond appear larger.

Also known as the teardrop, this shape with it’s single point and rounded end is a popular choice for a variety of diamond jewellery.

Trimmed corners are the significant feature of this diamond making it a popular and versatile choice for all styles of jewellery. Radiant cut can vary from square to various degrees of rectangularity.

Also known as ‘pillow-cut’ diamonds, this unique shape has been a popular choice for over a hundred years. It has rounded corners and its larger facets increase its brilliance and highlight its clarity.

The beautiful appearance of the heart-shaped diamond and it’s being, of course the ultimate symbol of love, make it a distinctive choice for a wide variety of diamond jewellery.


Identifying a Well Cut Diamond

In defining the best cut, personal preference will always be an issue. So the listed category Well Cut, Very Good, Excellent & Ideal assists you in selecting the right diamond. Ideal cut has the narrowest range, with Excellent and Very Good following later. The lowest score becomes the overall cut grade. The lowest assigned grade for any individual characteristic is always used. For e.g. If the table percentage falls within excellent and yet the depth percentage is in the very good range, the diamond is classified as Very Good.

When a ray of light touches the surface of a diamond, art of the light is reflected back, this is external reflection.
The rest of the ray penetrates the stone and is then reflected towards the center of the diamond. This is known as refraction.

The ray of light is reflected to the surface, where it is seen as the colors of the spectrum. This is known as dispersion.


The different diamond shapes do not all have the same proportions. Each diamond shape requires its own guidelines in order to achieve maximum beauty. Due to mathematical differences, inherent in different shapes, the table and depth guidelines are formulated to maximize fire & brilliance. This is done to have a magnificent display that highlights the individuality and character of each shape.


The girdle is the outer edge of a diamond. It usually has a frosted appearance. Many diamonds are also finished with a fully polished or even a faceted girdle. This characteristic does not affect the value of a diamond and is often more a reflection the diamond cutter’s preference. The girdle is rated in terms of thickness. Girdle size is generally defined as Extremely Thin, Very Thin, Thin, Medium, Slightly Thick, Thick, Very Thick, or Extremely Thick. The girdle can also be described as a range of these terms such as Thin to Thick. Avoid the two Extremes. When purchasing a diamond, select one with a girdle that is neither Extremely Thin nor Extremely Thick.

The culet is the bottom point of the diamond. In many cases this point actually has a very small facet. The culet is referred to in terms that relate to the presence or size of this facet. The culet is generally graded as None or Pointed, Very Small, Small, Medium, Slightly Large, Large, Very Large, and Extremely Large. Smaller is more desirable.

This characteristic refers to the finishing or final polishing of the facets, or flat surfaces. Contrary to common belief, diamonds are ground and polished, not chipped away, until they reach their final form. Each facet should be carefully fashioned by the diamond cutter to shine and be free from polishing imperfections. The polish of a diamond is generally defined as Poor, Fair, Good, Very Good, or Excellent. When purchasing a diamond, select one with a polishing grade of Good or above.

This characteristic refers to the alignment and positioning of the facets, or flat surfaces. Each facet should be carefully positioned by the diamond cutter in proper proportion and relationship to the other facets. The alignment of each facet should be sharp and precise; improperly joined facet junctions can make a diamond appear uneven. The symmetry of a diamond is generally defined as Poor, Fair, Good, Very Good, or Excellent. When purchasing a diamond, select one with a symmetry grade of Good or above.

This characteristic refers to the diamond’s ability to fluoresce under ultraviolet light. When exposed to UV light, many diamonds will give off a distinctive glowing blue coloration. Although fluorescence may be displayed in various shades, blue is the most common in diamonds. The fluorescence of a diamond is defined by its intensity as either None, Faint, Medium, Strong, or Very Strong. Most of the time fluorescence isn’t an issue unless the intensity is Strong or Very Strong. In the very high colors D, E, and F, Strong fluorescence is considered less desirable. Ironically, in slightly lower colors of J and below, Strong fluorescence is desirable.

2 - Colour

Although most diamonds appear colourless, virtually all have a tint of body colour. As the tones become more apparent, so the rarity and cost decrease. At Deonne le Roux Jewellers we use Colour Master Comparison Diamonds to determine where your diamond will be placed on the colour scale. The colour scale ranges from ‘D’ (colourless) to ‘Z’ (Tinted).

D,E,F Colourless
Ranging from the highest colour grade, which is extremely rare, to minute traces of colour detected by an expert gemmologist, but still considered a “colourless” grade. These are high-quality top diamonds.

G-H Near-colourless
Colour noticeable when compared to diamonds of better grades, but appear to the eye to be colourless when mounted. These grades offer excellent value.

I-J Slightly Tinted White
Colour slightly detectable. Diamonds in this category are the least expensive diamonds in the ‘white colour’ range, so you can buy a larger diamond for the same price as a higher colour grade.

K-M Tinted White
Slight yellowish colour. These diamonds are more suitable for two-tone and yellow gold jewellery.

N-Z Tinted Colour
Noticeable colour. These diamonds, when cut to ideal proportions, produces a warm brilliance not found in the higher grade colours. They work well with two-tone and yellow gold jewellery. Tinted colour diamonds present the best price in diamond colour, as they could cost 50% less than near colourless diamonds.

3 - Clarity

Even very high quality diamonds usually contain minute ‘crystals’, ‘feathers’ or ‘Clouds’, referred to as ‘inclusions’. In the higher quality diamonds these inclusions are only visible with a gemmologist’s microscope and, therefore, the diamond’s beauty is not usually affected.

As with colour, there are internationally agreed upon standards of grading. The fewer inclusions there are, the rarer and more valuable the diamond becomes. IF Internally Flawless – These diamonds are extremely rare and show no internal inclusions under magnification VVS1 & VVS2 Very, Very Small Inclusions - This diamond has very few, very tiny inclusions. The inclusions in this diamond are virtually unidentifiable under 10xmagnification. Diamonds of this grade of clarity are extremely rare.

VS1 & VS2 Very Small Inclusions
The inclusions are difficult to see under a 10x power magnification. VS grade diamonds present an excellent value in clarity because they are typically free of visible blemishes, and they are less expensive than higher clarity grades.

SI1, SI2 & SI3 Slightly Included
The inclusions are easy to find under 10x magnification but normally not visible to the unaided eye. Inclusions in diamonds with SI2 & SI3 grades clarity might be visible to the unaided eye. SI grade diamonds are not as rare as VVS and VS grade diamonds, so they are less expensive and present a great value.

I1, I2 & I3 Included
These diamonds have inclusions easy to find under 10x magnification and usually visible to the unaided eye. The inclusions could also have an effect on the stability and strength of the stone.

4 - Carat

Diamonds are sold by weight, measured in carats. One carat is equal to 1/5 of a gram and is divided into 100 points. So when you refer to a .75 carat diamond one could also say ¾ carat or 75 points. The scarcity of diamonds is what makes up part of its value. There is a staggering scarcity of large diamonds and this dramatically increases their value.