Everything you need to know about Diamonds


The factors affecting the value of a diamond are usually referred to as the four Cs. At Déonne le Roux Jewellers we suggest that you consider no less than seven Cs: Cut, Colour, Clarity, Carat, Certification, Confidence, Creativity.


1. CUT

Cut fuels the diamond’s fire, sparkle and brilliance.

Of all four Cs, the cut has the greatest effect on a diamond’s beauty. Déonne is a graduate gemmologist and hand selects most of our diamonds and gemstones. A sad fact is that about 75% of all rounds and 88% of other shapes of diamonds are poorly proportioned to contain carat weight rather than to maximise sparkle.


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 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 clarity 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 being, of course, the ultimate symbol of love, make it a distinctive choice for a wide variety of diamond jewellery.


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, part 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 colours 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 and 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 of 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.


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 Déonne 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.


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) – These diamonds have very few, very tiny inclusions. The inclusions in these diamonds are virtually unidentifiable under 10x magnification. 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.


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.


A diamond certificate is only a guide to its physical properties. The certificate should not be used as an indication of the diamond’s physical appeal. We always emphasize that a certificate should play only a small part in one’s choice.

Our valuation certificates describe, in detail, the quality of our diamond rings. Most of our diamonds over .50 carat are often accompanied by an independent diamond laboratory certification.



Limited Guarantee Certificate

We hereby guarantee that every item of jewellery purchased from Déonne le Roux Jewellers has been manufactured according to trusted modern production methods and has been subjected to comprehensive quality control. Should damage nevertheless take place that can be traced back to errors in material or production, we offer a one-year limited guarantee from the date of purchase. Please be informed that damage occurring as a result of normal wear and tear, accidents, mishandling or abusive use cannot be considered an error.

Exchange Policy

We take great care and pride in the selection and quality of our range. Gold and diamond jewellery purchased from us (excluding custom designed items) may be exchanged or refunded within 30 days of purchase, provided it is returned in its original condition. Please note that a watch can only be refunded or exchanged if it has never been worn and provided that it is brought back with its original packaging.

The Kimberly Process

The diamond industry established the Kimberly process to prevent the trade of conflict diamonds. Today, well over 99% of the world’s diamond supply is certified to be from sources that are free from conflict. As one of its major resources, diamonds are helping transform Africa and the lives of its people. At Déonne le Roux Jewellers we fully subscribe to the Kimberly process. We deal exclusively with suppliers who follow the guidelines of the Kimberly process to ensure that all the diamonds we sell are conflict-free.


A beautiful stone truly deserves a beautiful setting and the craftsmanship and quality of set work can dramatically alter your jewellery’s appearance. At Déonne le Roux, our dedicated, skilled and inspired design team will make every effort to ensure that all your requirements are not only met, but exceeded.

Countless, unseen details are often the only difference between Mediocre and Magnificent.

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