Diamond Anatomy & Cut Quality
When people think of “cut,” they often think of the shape of a diamond rather than its cut quality. Cut is all about a diamond’s fire, sparkle, and brightness, and as a value factor, it refers to a diamond’s proportions, symmetry and polish; those factors that determine the cut quality or the fourth ‘C. ‘
Understanding the 4 C’s of Diamonds Shopping
Take a few minutes to study the 4 Cs (Cut, Color, Clarity, and Carat) of diamonds below and become an informed engagement ring shopper.
Clarity
Clarity refers to how many ‘inclusions’ there are in a diamond. These inclusions are naturally occurring features – wisps of minerals, uncrystallised carbon, tiny fractures – formed deep within the diamond when it was created. Though usually invisible to the naked eye, they can influence the way light is reflected and refracted. A gemologist will examine a diamond under 10x magnification before assigning a clarity grade from F (Flawless) to I (Included). The grade may also indicate whether the inclusion is near the center of the stone or along its girdle, or outer edge.
Clarity Explained
Grading diamonds for clarity is the process for classifying the imperfections, both internal and external. Imperfections are called inclusions when internal and blemishes when external. The term clarity is preferred over purity because purity has a very narrow definition pure or impure. In order to accurately classify clarity in polished diamonds we need to have several levels of clarity.
Diamond Clarity Descriptions
FL-Flawless- These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10X magnification.
IF-Internally Flawless – This grade is awarded to diamonds with no internal flaws and only minor external blemishes. Nicks pits or girdle roughness, not on the table, which could be removed in re-polishing.
VVS1 , VVS2 – Very Very Slightly Imperfect – These stones have very, very small inclusions, which are extremely difficult to see under a loupe of 10X magnification.
VS1, VS2 – Very Slightly Imperfect – These stones have very small inclusions, which are slightly difficult to see under a loupe of 10X magnification.
SI1, SI2 – Slightly Imperfect – These stones have inclusions, which are fairly easy to see under with a 10X magnification, and can be seen with the naked eye.
I1, I2, and I3 – Imperfect – These stones have inclusions ranging from eye visible to very easily seen to the naked eye.
Cut
A diamond’s cut refers to the quality of the tiny surfaces, or facets. A well-cut diamond reflects light internally from one mirror-like facet to another and disperses it through the top of the gem. The facets, known as the crown, culet, table, girdle, and pavilion, are arranged with precise, mathematical proportions to maximise a diamond’s fire, life and brilliance. The cut, the only element of the 4Cs influenced by the human hand, is often considered the most important. A diamond that has been well cut may be given a higher quality or value than one that is larger or of a better colour.
Cut Explanation
Cut refers to the angles and proportions of a diamond, not the shape. It is the only one of the 4C’s that is influenced by the human hand. Diamond cutting requires great skill and training. The cutter must polish tiny surfaces known as facets onto the rough diamond. This process creates the facets known as the crown, culet, table, girdle, and pavilion of the diamond.
To cut a diamond perfectly, a craftsman will often need to cut away over 50% of the rough diamond. The better a diamond is cut, the more light it will reflect with the result that the diamond has more brilliance. This means that there are good and bad cuts in every shape.
As shown in the images below, when a diamond is well-cut, light enters through the table and travels to the pavilion where it reflects from one side to the other before reflecting back out of the diamond through the table and to the observer’s eye. This light is the brilliance we mentioned, and it’s this flashing, fiery effect that makes diamonds so mesmerizing.
In a poorly cut diamond, the light that enters through the table reaches the facets and then ‘leaks’ out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less a brilliant and less valuable stone. A well-cut diamond are therefore higher in quality and value than deep or shallow-cut diamonds.
Shapes & Cut Differences
Don’t confuse diamond “cut” with “shape.” Shape refers to the general outward appearance of the diamond, (such as round, emerald, or pear). “Cut” is a reference to the diamond’s reflective qualities, not the shape. The better a diamond is cut, the more light it will reflect with the result that the diamond has more brilliance. This means that there are good and bad cuts in every shape.
As shown in the images below, when a diamond is well-cut, light enters through the table and travels to the pavilion where it reflects from one side to the other before reflecting back out of the diamond through the table and to the observer’s eye. This light is the brilliance we mentioned, and it’s this flashing, fiery effect that makes diamonds so mesmerizing.
In a poorly cut diamond, the light that enters through the table reaches the facets and then ‘leaks’ out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance.
Diamond Cut Descriptions
The cushion diamond shape is made up of a square stone with rounded corners, and is an attractive alternative to the round brilliant or princess cut diamond shapes. Cushion cut is a generic name for the Old Mine Cut that was developed before the turn of the Century. The cushion diamond shape resembles a pillow, hence the name. It typically has 58 brilliant style facets.
Oval cut diamonds are brilliant cut with an elliptical girdle outline. It is also called an oval brilliant cut. It often appears larger than a round stone of the same weight. It was created in the 1960’s by Lasare Kaplan. A length to width ratio of 1.5:1 is a typical pleasing shape. Typically these stones have 56 facets.
The pear shape diamond is a variant of the brilliant cut. Also referred to as a Pear Shaped Modified Brilliant. This particular cut sometimes called pendeloque or teardrop has 56 – 58 facets. The name pendeloque is French and is related to our word for pendant. This is probably due to the pear shape diamond being a particulary good shape for use in a pendant.
The princess cut is a brilliant-style shape with sharp uncut corners. A princess cut generally has 76 facets giving it more brilliance and fire than a round brilliant. The princess cut diamond is one of the most popular cuts of diamond along with the round brilliant cut.
Radiant cut diamonds have the same look as a princess cut with the exception of the corners which are polished. It is possible to get both square and elongated radiant cut diamonds. Radiants are easier to find in the square or off-square proportions.
The round brilliant cut diamond is by far the most popular of all the polished diamond shapes. It consists of 57 facets (or 58 if a culet is present) While the facet count is standard, the actual proportions (crown height and angle, pavilion depth, etc.) can vary depending on how the diamond is cut.
A trilliant cut diamond is an unusual eye-catching shape. The name Trilliant is a combination of brilliant and triangle and sums up the shape perfectly. Usually cut with 44 facets, this is one of the more unusual yet striking cuts of diamond. It is possible to find a great variation in trilliant diamond sizes and weights, ranging from more deeply cut stones, to stones with a very large spread. The sides of a trilliant diamond can be straight, or can bow outward slightly with subtly curved edges.
Emerald Cut diamonds are usually rectangular in form. They are step cut diamonds with diagonally cut corners and two, three or four rows of facets, parallel to the girdle on the crown and pavillion. The look of an emerald cut diamond is subtle and understated and it has less flash than a brilliant cut. The Emerald cut diamond has been around for a long time and is one of the classic fancy cuts. When matched with outer diamonds, it is best to go for a similar cut of stone, such as baguette diamonds, tapering baguettes or smaller emerald cuts. The proportion of an emerald cut is typically a length measuring approximately 1.5-1.75 times the width, although variations are common.
The heart shape diamond is a modified brilliant cut in the shape of a heart. Also known as a Heart Shaped Modified Brilliant. It has a crown shaped table, and typically has 59 facets. The heart shape diamond is perhaps the most romantic of all the fancy cuts. The length to width ratio is normally 1:1 but as with many shapes, variations are often found.
The marquise shape is an elongated boat shaped brilliant cut with curving sides and pointed ends. It was developed in France in the 1740’s. It was supposedly named after King Louis XIV desired a stone to be polished into the shape of the mouth of the Marquise de Pompadour. This shape is also sometimes named Navette. Proportions vary, but a typical ration is 1.85 :1 to 2:1. The shape is something which is of personal taste with some people prefering a more narrow stone and vice versa.
Color
White or colourless diamonds actually occur in a range of shades – from truly colourless to off-white. They are graded on a colour scale from D (colourless) to Z. The differences between one shade and the next are very subtle, so grading is done under controlled lighting, using a master diamond sample set for comparison and accuracy. Natural diamonds also occur in shades of blue, green, yellow-orange, pink, red and even black. Known as ‘coloured fancies’, these gems are extremely rare and valuable. They are graded according to the intensity of their colour.
Diamond Color Descriptions
When we speak of colour in diamonds, most people think of the beautiful reds, blues, and yellows we see when a diamond flashes in the sun light. In fact grading a diamond for colour means deciding by which amount the diamond’s “body colour” deviates from the whitest possible (water like colourless) colour. Nature provides a continuous darkening in the tints from white to yellow, white to brown, and white to green. Divisions are determined by the ability of the human eye to separate one tint from an adjacent one that is slightly lighter or darker. This concept should not be confused with the sparkle, brilliance, or scintillation of the diamond.
Diamonds are graded on a colour scale which ranges from D (colourless) to Z. Warmer coloured diamonds (K–Z) are particularly desirable when set in yellow gold. Icy winter white coloured diamonds (D–J) look stunning set in white gold, platinum or palladium. Colour differences are very subtle and it is very difficult to see the difference between an E and an F, for example. Therefore, colours are graded under controlled lighting conditions and are compared to a master set for accuracy. Truly colourless stones, graded D are treasured for their rarity. Colour, however, is subjective. The Incomparable, one of the world’s most beautiful diamonds, contains hints of brown, smokey amber and champagne colours.
Because of the diamond’s high brilliance and dispersion of light, the colour grade cannot be accurately determined by looking at the stone from the top (face up) position. It is best to observe colour by examining the stone through the side of the pavilion (bottom of the stone) with the diamond upside down in a white paper grading through. Please note in the illustration below the stone can be examined in several positions to obtain an accurate colour grade.
Carat (Size)
Carat is a measure of weight, not size. One carat is equal to 200 milligrams. The term is derived from the word ‘carob’. Carob seeds were used as a reference for diamond weight in the ancient world. Because larger diamonds are rare, they are more valuable than the equivalent weight in several smaller diamonds. A one-carat diamond will generally cost more than two half-carat diamonds, assuming all other qualities are equal.
