The first step in choosing a diamond is deciding what shape you want. While the round shape is the most popular, there's plenty of other beautiful shapes to choose from which deliver brilliance and fire.
Of course, the most popular and commonly seen shape for diamonds is the round or brilliant cut, which has 57 or 58 facets (depending on whether the culet, or point at the bottom of the stone, is faceted or not). It's the 'classic' shape that most people think of when they think of a diamond. But the round cut is by far not your only choice. All shapes are capable of fantastic fire and brilliance. The only difference is the result of the diamond cutter's decision to cut the rough diamond into that particular shape.
Choosing the best shape for you
The most important factor in determining shape, of course, is what appeals to you, and what looks best on your hand. Longer and shorter stones can visually affect the appearance of your hands, making them look longer or shorter in return. Also, your taste may guide you toward more traditional shapes, like the classic round brilliant, or toward less conventional shapes like pear, marquise or heart. While the shape of the diamond you choose is ultimately a matter of personal preference, there are differences in the various shapes that affect their brilliance, apparent size and value:
- Round brilliant-cut diamonds show the most brilliance and sparkle of all the shapes. When it comes to hiding imperfections, the round brilliant cut is the king. Its design allows it to hide flaws and yellow tints better than diamonds of other shapes. In emerald cuts and baguettes, which have long, flat facets, flaws become the most obvious.
- Emerald cuts, while sleek and attractive, are not quite as brilliant. If you like the square or rectangular shapes of an emerald cut, you may want to consider a radiant, princess or quadrillion, which have more facets and therefore more brilliance.
- If you want a diamond that looks as big as possible, even if it doesn't weigh much, consider a fancy shape like a marquise or pear, which appear bigger and longer than round diamonds of the same carat weight.
Cut is the result of a craftsman's skill in transforming a rough diamond into a breathtaking gem. A diamond has facets that allow light to enter it, become refracted, and exit in a rainbow of colors. So it follows that a better cut diamond does a better job of dazzling us with its beauty. Here's the 'secret' to how a diamond sparkles:
As you can see, the diamond with the correct proportions does a more effective job of refracting light out the top of the stone to your eye. The less-than-ideal cut diamonds allow some light to become lost out the bottom.
There are many measurements that go into creating a diamond that truly maximize the refraction of light. Facets must be cut at exactly the right angles relative to one another; the top and bottom halves of the stone must have the proper depth relative to each other; the table, or flat surface on the top, must be the correct size, relative to the overall size of the stone. And, of course, the facets on the top (crown) and bottom (pavilion) must align correctly with each other. Here is a diagram showing a diamond's basic proportions:
These measurements and percentages are different for each diamond, and are all taken into account in the evaluation of a diamond's cut. In fact, each diamond shape (heart, round, oval, emerald, etc.) has its own set of guidelines for what makes a Premium or Good cut.
An 'ideal cut' is a specific set of guidelines that delineate the proportions that give a diamond the highest amount of fire and brilliance.
Although the proportions of an ideal cut vary depending on the source you talk to (from jeweler to jeweler, country to country), there are certain ranges that are generally accepted as capable of evoking the most desirable fire and brilliance from a stone. These ranges must cause the light entering the diamond to be reflected and dispersed through the table (top), not through the sides or bottom.
But most of all, an ideal cut diamond must be cut to bring out the stone's brilliance and fire, not retain the most weight from the rough cut stone.
Diamond.com's Diamond Proportion Guidelines
Diamond.com maintains extremely stringent guidelines for diamond quality. All diamonds we offer must fall within specific ranges to be judged acceptable by our staff gemologists.
Below is a table listing each of our three cut grades for a round brilliant diamond (Ideal, Premium and Good). The table percentage given is the measurement of the diamond's table width, relative to the width of the entire stone (at its girdle, or widest point). This relationship is critical for maximum fire and brilliance: too small or too large a table can hamper the diamond's ability to disperse light properly, not to mention possibly causing the stone to appear smaller for its weight.
The depth percentage listed is the length of the stone from table (top) to culet (bottom), expressed as a percentage of the diamond's width, measured at its widest point. This depth-to-width relationship is largely responsible for the diamond's being properly proportioned, resulting in the proper refraction of light and maximum fire and brilliance. |
The most important thing to know about diamond color is, in general, the less color a diamond has, the more valuable it is, all other factors being equal.
Diamonds are found in nature in a wide range of colors, from completely colorless (the most desirable trait) to slightly yellow, to brown. So-called 'fancy color diamonds' come in more intense colors, like yellow and blue, but these are not graded on the same scale.
The diamond color grading system uses the letters of the alphabet from D through Z, with 'D' being the most colorless and therefore the rarest and most valuable, and 'Z' having the most color within the normal range, and being the least valuable, all other factors being equal. A diamond's color is determined by looking at it under controlled lighting and comparing them to the Gemological Institute of America's color scale, which is based on a set of diamonds of known color. Here is a diagram showing how a diamond's color is graded
Diamonds found in nature come in colors ranging from colorless to slightly yellow or brown, to more rare and costly pink, green or blue stones (commonly referred to as 'fancy' diamonds). Excluding 'fancy' diamonds, the ideal color for a diamond is colorless, although this is extremely rare.
A diamond's color is most accurately determined when it is not mounted in a setting, since settings can introduce tints of their own color into the diamond. This is more evident in yellow gold settings, and less so in white gold and platinum settings. Even a trained professional can't always tell the difference between close grades of color in a diamond if it is still mounted in a setting. For this reason, gemological laboratories such as the Gemological Institute of America (GIA) and American Gemological Society (AGS) will only grade diamonds that are unmounted.
Diamonds with a color grade of D, E or F are considered colorless; G, H, I and J are near colorless; K, L and M have a faint yellow tint; N, O, P, Q and R have a very light yellow tint and S, T, U, V, W, X, Y and Z are light yellow. A diamond that is a D color is absolutely colorless, and is therefore the most valuable. However, it's important to understand that color alone does not determine the value of a diamond. All '4Cs' must be taken into account. A diamond of D color that has imperfections or is poorly cut is not as valuable as a stone of a lower color grade that has a superior cut and clarity.
The bottom line
A diamond's color also has a great impact on its cost. Since ''colorlessness'' is the most sought-after trait in terms of color, diamonds that are higher up on the color scale (e.g. D, E, F) will have a greater value. If a diamond with a specific cut, clarity and carat weight is moved to the next color grade, it's possible to see a significant increase or decrease in the per-carat price--all other factors being equal. The idea is to choose a diamond that is as high on the color scale as your budget will allow, taking all 4Cs into account.
A diamond's weight is measured in what is known as a 'carat', which is a small unit of measurement equal to 200 milligrams.
Carat is not a measure of a diamond's size, since cutting a diamond to different proportions can affect its weight. (The word 'Karat' is used to express the purity of gold, and is not used in relation to diamonds.) Here is a diagram that shows the relative size of various carat weights in a diamond that is cut to the same proportions:
Note: the diamonds illustrated are not shown actual size. You may also
print a PDF file with the actual sizes.
Carat Weight Scale
The most important thing to remember when it comes to a diamond's carat weight is that it is not the only factor that determines a diamond's value. In other words, bigger does not necessarily mean better. All four Cs-Cut, Color, Clarity and Carat Weight must be balanced in order to arrive at a diamond that fits your budget. None of the 4Cs is mutually exclusive, nor is any one more important than the others.
The word carat actually comes from the word carob (as in carob seeds), which is how ancient cultures measured the weight of diamonds on their scales. In 1913, however, the weight was standardized internationally and adapted to the metric system.
Although they can be measured when mounted in jewelry, diamonds are most accurately weighed when they are not mounted in a setting. In fact, gemological laboratories such as the Gemological Institute of America (GIA) and American Gemological Society (AGS) will only grade diamonds that are unmounted. A diamond grading report will tell you the exact carat weight, to the nearest hundredth of a carat, for that particular diamond. Each Carat is divided into 100 parts called 'points.' So a 1-carat diamond has 100 points, a 3/4 carat has 75 points, etc. Points in a fraction of one carat are measured within ranges, so that a 3/4 carat diamond may have between .69 and .82 points and still be considered a 3/4 carat. Here's a table of size and weight ranges:
Carat Fractions and Their Decimal Equivalents:
| CARAT FRACTIONS | | DECIMAL EQUIVALENT |
| 1/10 | = | .09 - .11 |
| 1/8 | = | .12 - .13 |
| 1/7 | = | .14 - .15 |
| 1/6 | = | .16 - .17 |
| 1/5 | = | .18 - .22 |
| 1/4 | = | .23 - .28 |
| 1/3 | = | .29 - .36 |
| 3/8 | = | .37 - .44 |
| 1/2 | = | .45 - .58 |
| 5/8 | = | .59 - .68 |
| 3/4 | = | .69 - .82 |
| 7/8 | = | .83 - .94 |
| 1.0 | = | .95 - 1.05 |
Remember, all diamonds are not created equal. Two diamonds of equal Carat Weight may vary substantially in price due to their Cut, Color and Clarity. Also, a diamond's weight can be 'hidden' in different parts of the stone. For example, you can have a well-cut diamond, whose weight is distributed properly, a diamond that is cut too shallow to make it wider and heavier, but not the most brilliant, or one that is cut too deeply, to add weight to the bottom of the stone - again compromising its ability to radiate maximum brilliance.
The bottom line
The carat weight of a diamond is an extremely important determining factor in its value. Diamonds are valued on a per-carat basis. For example, a diamond of exceptionally high quality may sell for $20,000 per carat, while one of lesser quality may sell for $1,000 per carat. So, a three-carat stone could be $60,000 or $3,000, depending on its per-carat price. Diamond values also increase disproportionately as the size of the stone increases. In other words, a two-carat stone will not necessarily cost twice per carat than a one-carat stone. It could cost much more, since diamonds are rarer in larger sizes. As you take a stone of a particular cut, clarity and color and move its carat weight to the next price category, you may see quite a large increase in the price per carat. Remember that size isn't everything. When choosing a diamond, all 4Cs must be taken into account. The key is to strike a balance among them, while still working within your budget.
A diamond grading report is a detailed explanation of a diamond's characteristics such as its cut, weight and dimensions. Many diamonds are certified by an independent laboratory so that purchasers can feel confident that their diamond is indeed of the quality the seller represents. A certified diamond's quality is guaranteed, and is therefore more valuable than an uncertified stone. A certificate verifies a diamonds identity and value and is recognized by all gemologists.
Diamonds are certified by independent grading entities whose expert gemologists evaluate each diamond's particular characteristics and attributes, such as clarity, cut, color, carat weight, fluorescence and other characteristics. Loose diamonds from Diamond.com are graded by either the GIA (Gemological Institute of America), AGSL (American Gemological Society Laboratories), or IGI (International Gemological Institute), the world's most respected grading entities. All of these institutes including the GIA, IGI and the AGSL are known for their consistency, stringency and impartiality when grading diamonds.
Below is a sample diamond grading report from the Gemological Institute of America, the foremost authority on diamond grading. The majority of diamonds you'll find at Diamond.com come with a GIA report.
A diamond grading report from an independent laboratory is not an appraisal, which estimates the monetary value of a particular stone. It is an unbiased, informed opinion made by an experienced gemologist. You will receive the original certificate or report with your diamond order.
Purchasing loose diamonds accompanied by certificates allows one to comparison shop and know exactly what they are getting. The slightest change in a diamond's grading can significantly alter its value.
There's no magic answer to the question, "which 'C' is the most important one?" The fact is, finding the best diamond for your money is a delicate balancing act among the 4Cs. For example, you may have to choose a lower Carat weight in order to find a diamond with better Clarity for the budget you've set. Or you may decide to trade a slightly lower Color grade in order to get a stone with a better Cut, etc. Excluding carat weight as a factor, the highest quality attainable in a diamond is a "D" color, IF (internally flawless) clarity stone that is Ideal Cut, meaning it gives off the maximum amount of fire and brilliance. You'll have to decide, based on your budget, how close to this ideal you wish to come.
The carat weight of a diamond is an extremely important determining factor in its value. Diamonds are valued on a per-carat basis. For example, a diamond of exceptionally high quality may sell for $20,000 per carat, while one of lesser quality may sell for $1,000 per carat. So, a three-carat stone could be $60,000 or $3,000, depending on its per-carat price. Diamond values also increase disproportionately as the size of the stone increases. In other words, a two-carat stone will not necessarily cost twice per carat than a one-carat stone. It could cost much more, like three times. This is because diamonds are more rare in larger sizes, so increases in size can mean disproportionate increases in value. As you take a stone of a particular cut, clarity and color and move its carat weight to the next price category, you may see quite a large increase in the price per carat. This jump gets proportionately larger as the number of carats increases.
A diamond's cut is a complicated evaluation based on many factors, including depth and table percentages, crown angles, girdle thickness and others. Added to that, some independent grading laboratories do not grade cut, like the Gemological Institute of America (GIA), making the determination even harder to quantify. We can, however, tell you that an ideal cut diamond generally garners a 20 to 30% higher price than one that is just "good". A diamond's shape can also affect its value, although usually to a lesser degree than its cut does. The reason for price differences between stones of comparable quality and size is primarily due to their supply and demand at a particular time, as well as the cost of the specialized labor skills needed to cut more intricate, fancy shapes. It is also less time consuming to cut, measure and select small round-shaped diamonds than small diamonds of more complicated shapes. Generally speaking, because of the popularity and demand for larger round diamonds, they usually cost more than fancy-shaped diamonds of comparable size and quality. There is very little differentiation in the value of comparable quality diamonds that have been cut into emerald, square or rectangular brilliant-cut shapes.
How a diamond's Color affects its value
A diamond's color also has a great impact on its cost. Since ''colorlessness'' is the most sought-after trait in terms of color, diamonds that are higher up on the color scale (e.g. D, E, F) will have a greater value. If a diamond with a specific cut, clarity and carat weight is moved to the next color grade, it's possible to see a significant increase or decrease in the per-carat price-- all other factors being equal.
How a diamond's Clarity affects its value
Since clarity, or the measure of imperfections or blemishes in a diamond, is so critical, it will of course result in price differences. If a diamond of a particular cut, color and carat weight is moved to the next clarity grade, it's possible to see a significant increase or decrease in the per-carat price-- all other factors being equal.
