Anatomy of Diamonds

The characteristic chemical composition and crystal structure of diamond make it a unique member of the mineral kingdom.

The way a mineral forms helps determine its identity. Diamonds form under high temperature and pressure conditions that exist only at a depth of about 160 kilometers beneath the Earth's surface. The crystal structure of diamond consists of carbon atoms bonded essentially equally in all directions. The result is that diamond is so hard it can only be scratched by another diamond.

Without these factors, diamond could simply be another mineral. Fortunately, this special combination of chemical composition, crystal structure, and formation process gives diamonds the properties that make them exceptional.

Diamond is now recognized on almost all modern birthstone lists as the birthstone for April.

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When you buy a diamond, you are drawn to its brightness and sparkle at the jewelry counter and remain fascinated long after purchasing your diamond. To achieve maximum brightness and sparkle, excellent cutting technique is required, reflected in the diamond's cut quality. Of the 4Cs, no other "C" has more influence on a diamond's appearance.

When people think of "cut," they often think more about the shape of a diamond than its cut quality. Cut refers to the fire, brilliance, and brightness of a diamond. As a value factor, it relates to the proportions, symmetry, and polish of a diamond; the factors that determine cut quality or the fourth "C."

When evaluating the cut quality of a diamond, numerous complex factors are considered: its proportions, the symmetry of its facet arrangements, and the quality of its polish or finish. The cut quality reflects the appearance of the diamonds.

Table: The table is the upper horizontal facet of the diamond. The average table size is expressed as a percentage of the diamond's average girdle diameter. While a diamond rated "Excellent" will have a table size between 52 and 62 percent, other proportions are also important.

Total depth: The total depth of the diamond from the surface of the table to the culet, expressed as a percentage of the average girdle diameter.

Pavilion depth: The pavilion is the lower part of a diamond from the lower edge of the girdle to the culet. Pavilion depth is expressed as a percentage of the average girdle diameter. A pavilion depth that is too shallow or too deep allows light to escape from the side or bottom of the stone. A well-cut diamond directs more light upward through the crown.

Pavilion angle: The pavilion angle is another important dimension of the stone, especially regarding the brightness of a diamond. This is the average of the angles formed by the main facets of the diamond's pavilion and its girdle plane. It should be between 40.6 and 41.8 degrees to be considered "excellent," provided other parameters also fall within their correct ranges.

Crown height: The crown is the upper part of the diamond from the upper edge of the girdle to the table. The average crown height is expressed as a percentage of the average girdle diameter. It can affect both the dispersion and brightness of a diamond.

Crown angle: The crown angle is the angle formed where the bezel facets meet the girdle plane. The crown angle in a well-cut diamond ranges between 31.5 and 36.5 degrees. The crown angle has a major influence on the open appearance of a round brilliant cut. The best range of crown angles provides a path for outgoing light dispersion as well as additional contrasting directions for incoming light.

Star length: The horizontally projected distance from the point of the star facet to the table edge, relative to the distance between the table edge and the girdle edge. A well-cut diamond will be between 40 and 70 percent if other parameters are within the correct ranges.

Girdle Thickness: The girdle is the middle part of a diamond, a narrow section that separates the crown from the pavilion and serves as the setting edge of the diamond. Girdle thickness is described as a range from the thinnest to the thickest areas. A thick girdle is less desirable because it adds unnecessary weight to the stone where it counts least (making the diamond appear smaller). An extremely thin girdle is sometimes called a knife edge and results in a diamond that is more fragile and prone to chipping. Therefore, a girdle that is "medium to slightly thick" is preferred.

Lower Girdle / Half Facet Length: This ratio is measured by calculating how long the lower girdle facets are relative to the length of the pavilion. This defines the contrast of a round brilliant cut, which controls the brilliance of a diamond. A well-cut diamond ranges between 65 and 90 percent. Diamonds with longer lower half facets have a bit more sparkle.

Culet: The culet is the small facet at the bottom of a diamond, designed to prevent chipping and abrasion at the tip. The size of the culet can affect the appearance and is referred to as the average width of the facet. The size is described as none, very small, small, medium, slightly large, large, very large, and extremely large. If there is no culet, it is sometimes called a pointed culet. Preferably, the culet is not visible to the naked eye, and when described as none (no culet), it falls into the excellent range.

Four Cs – Carat, Clarity, Cut, Color

CARAT (ct.)

Diamonds are sold by carat (represented as ct.), which is actually a unit of weight, although most people think of carat in terms of size. The word "carat" comes from the carob seed, the original unit of measure for diamond traders. One carat is exactly 0.2 grams today (about the weight of a paperclip). Carat weight has nothing to do with the similarly sounding term karat, which refers to the purity of gold.

Two diamonds with the same carat weight can vary greatly in price due to other factors (such as cut, color, and clarity). If you understand the meaning of carat weight, you know your partner. If the recipient's heart is set on a particular diamond size, carat weight will likely be the most important factor in your search until the desired size is reached, after which other criteria become more important. Most women can tell you the carat weight and shape of their ideal diamond, and most men can tell you the price.

As the carat weight of a diamond increases, the price of the diamond rises at an increasing rate. Why? Because the diamond becomes rarer as it gets larger. Less than one in a million mined rough stones is large enough to produce a finished 1-carat diamond.

It is important to note that not all diamonds have the same carat weight. Due to differences in depth and cut, two diamonds with identical diameters can actually be two completely different sizes. Therefore, it is possible to buy a diamond that looks larger than another but actually has a lower carat weight. When purchasing a diamond, you should consider the length, width, and depth of a stone as well as the surface of the diamond (the part that is actually visible when the diamond is set).

CLARITY & COLOR

A flawless diamond with few to no imperfections is often sought after due to its rarity, but they are also the most expensive, so it is important to keep in mind that diamonds often form with slight imperfections.

These imperfections are called "inclusions" and usually occur during the crystallization period of the diamond in the earth or due to stresses during mining and processing. Inclusions range from tiny white dots to dark spots, cracks, or scratches. The fewer inclusions, the more valuable a stone is. Clarity is assessed with 10x magnification. This means the object viewed is ten times its actual size. The diamond grader considers clarity characteristics in terms of type and number of features as well as their size, color, and position.

There are six main quality grades for diamonds. The highest is called Flawless (denoted as "FL"), followed by the next best grade, Internally Flawless (IF).

The main difference between VVS and VS clarity is the size of the inclusions.

VVS (Very, Very Slightly Included) and VS (Very Slightly Included) are the next two grading ranges. (You should remember that VVS means a higher quality than VS.)

The two lower quality grades are Slightly Included (SI) and Included (I).

What is VVS clarity?

Diamonds with VVS clarity have very minor imperfections that even trained professionals cannot easily detect with a loupe or microscope.

The VVS grading range is divided into two subclasses: VVS1 and VVS2, with VVS1 being the higher grade.

What is VS clarity?

Diamonds with VS clarity have inclusions that are usually difficult to see under 10x magnification. A small number of these imperfections may be more easily visible, but they are still tiny. Like VVS clarity, the VS grade is also divided into VS1 and VS2.

VVS diamonds have smaller inclusions

The main difference between VVS and VS clarity is the size of the inclusions: VVS diamonds have smaller and less visible flaws. Even when you look at these stones under a microscope, it is usually difficult to see inclusions.

VS diamonds, on the other hand, have some inclusions that are easily visible under magnification. Most flaws are still microscopic, but at least one or two of them are larger and easily seen with a jeweler's loupe. Remember that these are still inclusions and are not visible to the naked eye. A superior cut or superior color can make a VS diamond more expensive than a VVS stone, so you should also evaluate other quality characteristics. With equal affordability, VS clarity is the clear winner.

Remember that the differences between VS and VVS can only be seen with a microscope or a 10x loupe. You cannot distinguish them with the naked eye.

Cut (Diamond Cut)

People often use the words "cut" and "shape" interchangeably when talking about diamonds. However, these two terms have slightly different meanings. Shape refers to the overall outline of a stone. Although a particular cut implies a certain shape, the term cut technically refers to the number, arrangement, shape, and proportions of a stone's facets. The shape of a diamond tells you what a stone looks like, while its cut gives you information about how that shape was achieved through cutting.

Technically, two diamonds can have the same or similar shape, but their cuts are considered different if their facets are arranged or shaped differently.

Ideal Diamond Cuts

Although there are a number of diamond cuts on the market, these are the ones most likely to be seen when buying jewelry:

Round Cut The round cut is perhaps the most popular diamond cut sold today. This is the cut specifically designed to maximize brilliance. Because of this, flaws and yellow tones in round cut diamonds are less visible than in stones of other cuts. Many consumers consider the round cut the classic diamond cut.

Princess Cut The princess cut is similar to the round cut in that both are brilliant cuts, but the princess cut has a rectangular outline instead of a round one. Although not as brilliant as the round cut, the princess cut is a good alternative if you are looking for a diamond with a square or rectangular shape that also has a good level of sparkle.

Emerald and Asscher Cuts The emerald cut is a rectangular step cut with clipped corners, and its square variation is called the "Asscher cut." The emerald and Asscher cuts differ only in outline, but the shape and arrangement of their facets are the same. These cuts do not have as much brilliance as the round or princess cuts, so any imperfections or tones in the emerald and Asscher cuts are more visible.

Cushion Cut Cushion cut diamonds appear rectangular or square, but their corners are rounded, making the shape of the stone look like a cushion. The cushion cut belongs to the group of brilliant cuts.

Radiant Cut The radiant cut has a rectangular or square shape with clipped corners. This is another brilliant cut often compared to the cushion cut. The radiant cut shares some features characteristic of the emerald cut, and this similarity leads some people to classify the radiant cut as a mixed cut.

Oval Cut The oval cut is another brilliant diamond cut and can be considered a modified version of the round cut. An oval cut diamond is a great choice if you want your jewelry to convey a sense of length, especially when the stone is set in a ring.

Marquise Cut Marquise cut diamonds have an oval outline but two pointed ends. These sharp points are particularly prone to chipping and should be properly protected by the setting when the diamond is mounted in jewelry.

Pear Cut The pear cut has an oval shape with one end pointed, giving the outline of this cut the appearance of a tear or pear. Pear cuts combine features of the marquise cut and the oval cut. If you have a pear-shaped diamond, make sure its pointed end is protected when set in jewelry.

Heart Cut The heart cut looks very similar to the pear cut, but the rounded end of a heart-shaped diamond has a cleft. When purchasing a heart cut diamond, make sure the left and right parts are symmetrical.

Trillion Cut The trillion cut has a triangular outline. The ends can be pointed or rounded. If they are sharp, they can chip easily, so they should be properly protected when worn. Trillion cut diamonds are often used as side stones but can also be worn as center diamonds.