A diamond may be large or small, tinted or white, with inclusions or none, but a rough unpolished diamond is never good or bad - it is a product of nature. For this reason selecting a diamond is a personal journey, one where your preferences matter. Rough diamonds are cut (polished) for sale and, when humans get involved, mistakes are made. A diamond may be cut well, or not well. This can ruin it's beauty by making it appear less bright or lack symmetry. Charles Rose diamonds are always perfectly cut, maximising beauty and brightness. Diamonds are normally graded as to their cut, colour, clarity and carat weight (also known as the four "C's"), however these parameters are not the full story. For example a diamond cut by a master can reveal enhanced beauty and scintillation that is beyond conventional grading, or a gem may have high fluorescence or poor certification. Charles rose diamonds are cut to ideal standard, most often rated Triple Excellent, and accompanied with diamond grading certification from independent diamond grading laboratories of the highest international reputation.
An uncut diamond is dull, but when "cut" (polished) its surface becomes transparent, revealing it's inner beauty and allowing light to reflect and refract back to the viewer creating brightness and scintillation. Diamond is crystallised carbon, the hardest material known to man, and can only be polished using other diamonds. This is achieved by holding the rough diamond against a spinning wheel infused with diamond dust, methodically changing the position of the gem to add flat facets and shaping it. If shaped to ideal proportions the diamond will be of maximum brightness. If the proportions of the diamond are not ideal light will be lost and the diamond will be less bright. Diamonds are often purposefully not cut to ideal proportion; typically this occurs when a cutter feels this will result in too much loss of weight or size. The end result is a larger or heavier diamond but one that is less bright - an undesirable outcome. Top grades are: "Triple Excellent (Xc, Xc, Xc)" and "ideal". Average grades are VG (Very Good) and G (Good). Charles Rose specialise in the supply of Triple Excellent/ideal cut diamonds. It is our view that the brightness of the diamond should not be traded away for greater size or weight.
Most diamonds are yellowish or brownish. Pure white diamonds are more rare and more popular. Whiteness in a diamond is simply an absence of colour. Beautiful fancy yellow, pink, green, (and other) coloured diamonds are possible, but the majority of diamonds are yellow / brown. White grades are very finely differentiated and most (non expert) people have difficulty telling the difference between the top 3 grades (D, E and F). Diamonds are colour graded when they are loose and turned over, to eliminate the distracting effects of settings and the quality of cut. After a few days of wearing a diamond ring the diamond will lose its pristine appearance and the subtlety of the top 3 grades will be somewhat academic (and not apparent even to experts). White (non-fancy colour) grades are: Exceptional White Plus (D), Exceptional White (E), Rare White Plus (F), Rare White (G), White (H), Tints: (I,J,K,L,M,N,0.....X,Y,Z). It should be noted that when viewed face up the whiteness of a diamond can be enhanced by the brightness of cut, another benefit of an ideal make (see above). The top grades for colour diamonds are: Vivid, Fancy Intense, Fancy and Light fancy. Fancy colour diamonds are often more valuable than high grade white diamonds.
Most diamonds tend to yellow, but many tend to brown. The hue of colour is referred to as "shade". Generally diamond colour results from carbon atoms bonding with atoms of nitrogen or boron. The colour is usually concentrated in one or more places but radiates out to visually infuse the whole gem. The four primary shades (Yellow, Dark Tinge, Brown and Dark Brown) are further classified as to intensity. There are practical implications regarding shade. For example very light brown (TTLB) diamonds typically sell better as discount stones (rather than light yellow shades) as they seem whiter in comparison, particularly when well cut. This perception is partly innate, and partly due to human conditioning - brown being less expected as a tint.
"Clarity" is a confusing term. It is only used because it is a "C" word and allows the use of the term "4C's". It should be an "I" word as it refers to the more formal term "inclusions". These are small marks in the diamond, typically small fissures or foreign crystals that do not have any effect on how "clear" a diamond is (in the common sense of the word). If a diamond is "eye clean" (SI grade to VVS1) the inclusions are not visible to the naked eye - they are only visible using a "loupe" (this is a 10x magnification hand lens used by diamond graders worldwide). If a diamond is "Loupe Clean" (also known as "flawless" see below) the inclusions are invisible even using the 10x lens. Of course if a magnification lens more powerful than 10x is used you would start to see inclusions again. There are in fact billions of inclusions in every diamond. Visible Inclusions are often used to identify stones. They can be distracting or even beautiful but usually they are referred to as "flaws" (another misnomer as they are entirely natural). Clarity grades are: FL (internally and externally flawless - ie also without surface blemishes), IF (internally flawless), Vvs (1/2), Vs (1/2), SI (1/2), Pk (1/2/3). Tiny inclusions can be so numerous that they form milky "clouds" in a gem. These clouds can be white or grey and stretch across the gem. Milkiness is also graded and common terms are: VSL (very slight), SL (slight), CVSL (centre very slight), CSL (centre slight), MED (medium) and Heavy. Milkiness can impact significantly on appearance and value.
Diamonds can be fluorescent. The fluorescence, when present, takes the form of a phosphorescent after-glow that occurs when the diamond is exposed to ultraviolet light - which includes sunlight. Fluorescence can be Nil, Faint, Medium, Strong or Very Strong. When faint, the effect can be positive - brightening and whitening the appearance of otherwise lightly tinted gems without affecting brilliance. With fancy colour gems the effect can be to enhance the colour further. Strong fluorescence can look oily or cloudy and reduce value considerably. In other cases the fluorescence can impart a yellow or orange hue to a white diamond to make it appear of a lower colour grade. It is important to understand the effect of fluorescence and to look out for it. Charles Rose diamonds are fluorescent free.
Diamonds are cut into a variety of shapes (see illustration above). There are more shapes than just these. Some shapes resemble butterflies and four leaf clovers etc etc!. Other shapes are proprietary (cut to retailer's specification) to be sold as "exclusives", however such shapes typically have inferior optical properties and are a gimmick. The most popular shape is still the classic round brilliant for it's bright and uniform optical properties. Also popular are square and rectangular shapes. As facets are added scintillation increases (for example with princess and radiant cuts), however fewer facets will give bigger "flash" (for example with emerald and baguette cuts). Some shapes are classics (ie they have been popular for decades), like emerald, baguette and cushion cuts. Contemporary shapes (ie popular over the last 15 years or so) include the princess, asscher and trilliant. Each shape affords the jewellery designer a different opportunity for expression. Combinations of cuts create additional jewellery design permutations. Square shapes are cheaper than round brilliants of the same quality. This is because the natural diamond crystal is square in cross section and less diamond is "lost" when cutting a square shape from it.
The weight of a diamond is expressed in "points" up to 99 points (for example 62 points, 25 points etc). 100 points is said to equal 1 carat. A diamond equal to or heavier than 1 carat is expressed in carats alone (for example 1.35 carat, 4.20 carat etc). 1 carat is equal to 1/5th of a metric gram. Diamonds of the same carat weight do not always have the same dimensions because diamonds are often not cut to ideal proportions. This is very common because diamonds are often cut for weight, not brilliance (see above). For example one carat sounds better than 98 points. This is also reflected in the price (for example a poorly cut 1 carat diamond can look smaller than a well cut .98 carat diamond but still cost more). Correctly cut ("ideal" or "Triple Excellent") diamonds have ideal dimensions. We have included here a link to a dimension/carat weight chart based on ideal cut gems. Click the link (on the right) to see the dimension/carat weight chart. If you print the chart without rescaling, it will print accurately the true physical sizes of different carat weights for different shapes of diamond. Unfortunately they look smaller on the page than in jewellery so do not be put off !