The 4 Cs

1. Cut
   The cut actually pertains to both the shape of the diamond and to the make (how well a diamond was fashioned to good proportions and polish). Shapes include round, marquise, princess, radiant, pear, oval, emerald, and heart, and a few rare shapes. The Make includes details such as table percentage, depth percentage, polish, and symmetry, among others.
   
   
2. Colour
   The colour of diamonds varies from colourless (highest quality) to many shades of yellow (less rare). Some people ignore the "popular" trend toward the colourless and prefer the warmth of light yellow tints.
   
   
3. Clarity
   Diamonds are a natural substance, and no two diamonds are exactly alike. Nature signs each of its creations with telltale inclusions, or internal flaws. A diamond with more inclusions will be less rare, so it will be less expensive. But this does not necessarily mean it will be less beautiful to the naked eye.
   
   
4. Carat Weight
   The weight of diamonds is measured in carats. Larger diamonds are much more rare, so a 2-carat gem will be worth significantly more than 2 diamonds of the same quality weighing 1 carat each.

 

Diamond Shapes

The first step in choosing a diamond often involves selecting your favourite (or her favourite) shape. The Round Brilliant is by far the most popular shape, and it is the most readily available in every possible quality and size.

Contrary to popular belief and perhaps your experience in most stores, fancy-shaped diamonds (as all non-round diamonds are called) are often less expensive than their round brethren... at the wholesale level.

The Princess cut is becoming popular because it is both brilliant and unique. The Princess shape actually saves money for a cutter, since it is closest to the octahedral "habit" of rough diamond crystal, the most common formation of diamond in the rough. (The octahedron is like two pyramids base to base.)

Compared to a Round Brilliant, a cutter can retain more of the original crystal when cutting an octahedron into a Princess shape. The square corners of the rough need to be cut away to create a Round, but they are saved when cutting a Princess.

The more he saves of his original rough crystal, the less the cutter loses on his financial investment in the stone, and therefore you pay less as well.

But many shapes can be beautiful if they are cut well, including the Marquise, Oval, Pear, Radiant, Heart, Emerald and other major shapes. But all fancy shapes have an inherent difference in the physics of light. The longer shapes have a slight "bow tie" effect. This means they have a small zone in the center where light leaks out the bottom, creating a darker area in the shape of a bow tie. This is especially true for the Pear, Oval, Marquise, and Heart shapes.

For ideal proportions that maximize brilliance, fire and sparkle, you can't beat the new Round Brilliant Ideal Cut. The science of cutting a diamond to bring out the full potential of its beauty has developed significantly in the past 10 years. Many diamond cutters now specialize in creating ideal proportions, and such stones have become quite popular. Ideal Cut diamonds command a slight premium because of the extra care and skill needed during cutting, more of the rough is usually cut away, and 3) they are scarce and in high demand.

 

Diamond Clarity

Clarity is one of the two best-known factors in diamond pricing, along with colour. While the colour does affect a diamond's appearance, obvious inclusions (often called "flaws") may distract your recipient's eye from a stone's overall beauty. We usually recommend diamonds without inclusions or flaws that are visible to the naked eye. This avoids inadvertent negative feedback from friends and ensures the wonderful, lifelong enjoyment of your diamond.

To achieve this, stay well above the I-1 clarity grade. Clarity grades of SI2 or above are defined as flawless to the naked eye, but SI1 is safer in larger sizes. It's not necessary to go all the way up to IF (internally flawless) to get a beautiful diamond. From SI1 and above, diamonds will appear the same to the naked eye, differing only in the other factors of the 4 Cs: including Carat weight, colour and Cut.

Clarity greatly varies from one diamond to another, and no two are exactly alike. The Gemological Institute of America established standardized clarity grades for the diamond trade which are now used worldwide among dealers to help in trading and valuation.

The following chart gives an idea how each grade might look under a 10x loupe microscope:

Clarity Grades

Below are some simplified definitions of the various clarity grades set by the Gemological Institute of America (GIA).

• FL (Flawless): no internal or external inclusions of any kind visible under 10x magnification to a trained eye, the most rare and expensive of all clarity grades.
• IF (Internally Flawless): no internal inclusions visible under 10x magnification to a trained eye, but there may be some tiny external irregularities in the finish.
• VVS-1 (Very Very Slightly Included 1): usually just one tiny inclusion visible only to a trained eye under 10x magnification.
• VVS-2 (Very Very Slightly Included 2): tiny inclusions visible only to a trained eye under 10x magnification.
• VS-1 (Very Slightly Included 1): very small inclusions visible with 10x magnification.
• VS-2 (Very Slightly Included 2): several very small inclusions visible with 10x magnification.
• SI-1 (Slightly Included 1): small inclusions visible with 10x magnification.
• SI-2 (Slightly Included 2): several small inclusions visible with 10x magnification.
• I-1 (Included 1): flaws that are visible to the naked eye.
• I-2 (Included 2): many flaws clearly visible to the naked eye that also decrease the brilliance.
• I-3 (Included 3): many flaws clearly visible to the naked eye which decrease the brilliance and compromise the structure of the diamond, making it more easily cracked or chipped.

 

Diamond Colour Grades

Colour in the diamond trade usually refers to the amount of yellow in a stone, but can also indicate brown or gray and sometimes all three. The most treasured diamond colour is actually the "colourless" grade -- one without any colour at all.

Today's standard colour grading scale was first developed by the Gemological Institute of America (GIA). Other colour scales are still used in other parts of the world. If you are looking at diamonds with non-GIA certificates,

The GIA scale starts with D for perfectly colourless stones, and gives a Z colour grade to diamonds having a noticeable yellow tint, with every letter between indicating the many gradations possible. Most people find colours D through L to be the most attractive, and they are the most rare as well. This means they are also more expensive. Some people prefer the pronounced yellow tints, so their chosen diamond will be much less expensive.

 

Diamond colours

Below are samples of several diamond colours (with variations depending on your monitor). Note the subtle differences among colours as you go down the alphabet from D (perfect, colourless) to Z (the most yellow and least expensive).

 

Most people never imagine that diamonds of other colours, called "fancies," are also available in very limited supply. Diamonds with more colour than the Z shown here include fancy yellow, canary yellow, and others. The more expensive and treasured stones have pure tints with very little brown or gray tones to wash the fancy colour. colours such as "intense purplish pink," perhaps the most rare and treasured of fancy diamond colours, might sell for as much as $125,000 per carat for 1-carat stones, wholesale

 

Carats

Diamond weights are measured in "carats." One carat equals 1/142nd of an ounce, or 1/5th of a gram. In other words... there are 142 carats in 1 ounce and 5 carats in 1 gram.

The word "carat" comes from the ancient practice in India (where diamonds were first discovered and traded) of measuring diamond weights with the one thing in nature that is both small and the most consistent in weight -- the carob seed. Thus the name "carat" evolved in the English language, which is still equivalent to approximately the weight of one carob bean.

Points

You also may have heard jewelers talking about "points" when discussing diamond sizes. This does not refer to the number facets on a diamond, but rather to its weight. Just like one pound is divided into 16 ounces, one carat is divided into 100 points -- so each point is 1/100th of a carat. A "10-point" diamond weighs 1/10th of a carat, and a 50-point stone weighs one-half carat.

Price

Carat weight has a great deal of influence on the price of a diamond -- more so than one might imagine at first. Since larger stones are more rare in nature, they are more expensive as well. For instance, one diamond weighing 2 carats will always cost much more than two diamonds of the same quality weighing 1 carat each.

Below is an approximate comparison of the major diamond weights to act as a starting point in your consideration.

 

Diamond Cut

The cut of a diamond refers to two different things: the shape (pear, round, marquise, princess, radiant, emerald, heart, or trilliant) and the make (the quality of the work in fashioning the shape).

Make of a diamond refers to how well a stone is cut and faceted to bring out the full beauty of the rough crystal. Good proportions, symmetry, and polish effect the beauty of a diamond much more than perfect colour or clarity.

With all the attention given to the 4 Cs of diamond grading and evaluation (cut, colour, clarity and carat weight), the make is actually the single greatest factor in the beauty. Oddly, the make is not generally graded on most laboratory certificates. (Only the American Gemological Society (AGS) assigns a grade to the make, with "0 deductions" being the best grade.)

Colour, shape, clarity and carat weight determine the rarity and value of a diamond, but the make determines its beauty. Without any cutting, bruting, faceting or polishing, a rough diamond might very well go unnoticed in a pile of rocks. It is the diamond's unique combination of durability, rarity and potential beauty that makes it so valuable.

Proportion is the single most important factor, because it determines the flow of light more than other quality factors. Proportions that are too deep or too shallow both allow light to leak out the bottom and lessen the amount of light that strikes your eye.

Diamond proportions have evolved over the last 100 years to increase the brilliance, scintillation and fire to dazzle the eye. Many details must be precisely managed and executed to create a truly beautiful diamond of excellent make.

Proportions determine a diamond's brilliance (amount of light reflected back to your eye), fire (the flashes of colour due to prismatic separation into the colours of the rainbow) and scintillation (sparkling movement of light as you move the diamond).

Below are the approximate proportions to create a round diamond of maximum beauty, achieving an excellent balance between brilliance, fire and scintillation. (NOTE: These proportions only apply to round diamonds. Detailed guidelines have not yet been determined for other shapes.)

Since we see the results every day in jewelry stores, we know that rough diamonds can be cut, but only by other diamonds -- usually in the form of diamond dust.

The rough diamond in the photo below is an excellent specimen of an octahedral crystal, the most common of the many shapes of rough diamond. This is called the habit of diamond crystal.

When such a crystal is fashioned into a brilliant jewelry gemstone, the diamond cutter takes the stone through many detailed steps, the most important of which are:

Cleaving

When a rough diamond is determined to be suitable, it is carefully studied for every detail of its structure. It will then be marked and given a sharp blow with a special hammer to separate the stone into two carefully planned parts. This is a risky undertaking, and only used in rare cases since the advances in mechanical cutting devices allow even the most difficult stones to be cut with little attention.

Cutting

In most cases, a diamond will be cut with a saw blade. Since diamonds are the hardest material known (which means they cannot be scratched with any other substance), only diamonds can cut diamonds. So the diamond is securely mounted and held against a thin alloy blade impregnated with diamond dust and covered with linseed oil. As the blade turns, it carries small particles of new diamond dust which sticks to the oil and continues the process until the entire diamond is split in two. This can take several days for a diamond over 1 carat or more.

Bruting

After a diamond is the height and width desired, it is crudely shaped into the round or other shape by rubbing it against another diamond on a high-speed lathe specially designed for the purpose. The bruter takes the rough from an octahedral shape to a more rounded shape in the case of many round brilliant diamonds.

 

 

Faceting

Then the long and precise process begins to create the many facets that you have seen on diamonds in stores. Each facet is created by grinding the diamond on a horizontal blade as it spins with diamond dust and linseed oil, similar to the cutting blade.

First, the large facet at the top is ground until level and smooth. Then the major facets are created on the bottom (called the pavilion), followed by the large facets on top (called the crown). Then the pavilion facets are refined into more facets, followed by the crown facets. The final touch is often the tiny flat facet at the point of the pavilion, called the culet. The finished round brilliant diamond, for instance, will have 58 facets, including the tiny culet and large table facets.

Each step in this delicate process is generally carried out by a specialist who spends many years in apprenticeship to accumulate the great skill required. Every tiny mistake can risk a gem worth thousands of dollars. Only experience can safeguard nature's treasures and bring out the true beauty of a diamond.

In addition to the proportions, polish effects the final cut grade too. A well-polished diamond produces sharp sparkle and undistorted brilliance and fire. If the polish is poor, even a well-proportioned, symmetrical diamond can look dull or fuzzy.

Ideal Cut diamonds from many manufacturers have become popular in the past few years, and for good reasons. Stones with these ideal proportions are noticeably more beautiful to most people. These are in high demand, however, and usually require more loss of the rough to achieve ideal proportions. These factors combine to cause a slight premium in price. Ideal Cut diamonds include name brands such as Hearts and Arrows, Hearts on Fire, Eight Star, and others.