Anatomy of diamonds

The diamond's characteristic chemical composition and crystal structure 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 below the Earth's surface. The diamond's crystal structure consists of carbon atoms that are bonded essentially evenly in all directions. The result is that diamond is so hard that it can only be scratched with another diamond.

Without these factors, diamonds could be just 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 as the birthstone for April on almost all modern birthstone lists.

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When you purchase a diamond, you're drawn to the jewelry counter by its brightness and sparkle, and you remain captivated long after your purchase. Achieving maximum brightness and sparkle requires excellent cutting technique, which is 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 of a diamond's shape rather than its cut quality. Cut is about a diamond's fire, luster, and brightness. As a value factor, it refers to a diamond's proportions, symmetry, and polish—the factors that determine cut quality, or the fourth "C."

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

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 bottom 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 a stone, especially in relation to a diamond's brightness. 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 fit within their proper ranges.

Crown height : The crown is the upper part of the diamond, from the top 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 is between 31.5 and 36.5 degrees. The crown angle greatly influences the open appearance of a round brilliant cut. The best range of crown angles provides a path for outgoing light scattering 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 range between 40 and 70 percent if other parameters are within the correct ranges.

Girdle Thickness : The girdle is the center portion of a diamond, a narrow section that separates the crown from the pavilion and serves as the diamond's setting rim. Girdle thickness is described as the range from the thinnest to the thickest areas. A thick girdle is less desirable because it adds unnecessary weight to the stone where it matters 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 a diamond's brilliance. A well-cut diamond falls between 65 and 90 percent. Diamonds with longer lower half facets have slightly 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. When there is no culet, it is sometimes referred to as an acute 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 the carat (represented as ct.), which is actually a unit of weight, although most people think of carats in terms of size. The word "carat" comes from the carob seed, the original unit of measurement for diamond dealers. One carat today is exactly 0.2 grams (about the weight of a paper clip). Carat weight has nothing to do with the similar-sounding term karat, which refers to the purity of gold.

Two diamonds of the same carat weight can cost very differently depending on other factors (such as cut, color, and clarity). If you understand the importance of carat weight, you know your partner. If the recipient's heart is set on a certain diamond size, carat weight will likely be the most important factor in your search until you reach the desired size, 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 a diamond's carat weight increases, its price increases at an increasing rate. Why? Because the diamond becomes rarer as it grows. Fewer than one in a million mined rough stones is large enough to produce a finished 1-carat diamond.

It's 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's possible to buy a diamond that appears larger than another that may actually have a smaller carat weight. When purchasing a diamond, you should consider the length, width, and depth of a stone, as well as the diamond's surface area (the part that's actually visible when the diamond is set).

PURITY & 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 remember that diamonds are often formed with slight imperfections.

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

There are six main quality grades for diamonds. The highest is Flawless (denoted as "FL"), followed by the next highest 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. (Note that VVS indicates higher quality than VS.)

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

What is VVS clarity?

VVS clarity diamonds have very minor imperfections that even trained professionals cannot easily detect with a magnifying glass or microscope.

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

What is VS purity?

Diamonds with VS clarity have inclusions that are typically 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 viewing these stones under a microscope, inclusions are usually difficult to see.

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 will be larger and easily visible with a jeweler's loupe. Keep in mind that these are still inclusions and not visible to the naked eye. A superior cut or color can make a VS diamond more expensive than a VVS stone, so you should also evaluate other quality characteristics. Given equal affordability, VS clarity is the clear winner.

Keep in mind that the differences between VS and VVS can only be seen with a microscope or a 10x magnifying glass. You can't tell them apart 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 general outline of a stone. Although a particular cut implies a specific shape, the term cut technically refers to the number, arrangement, shape, and proportions of a stone's facets. A diamond's shape tells you what a stone looks like, while its cut tells you how that shape was achieved by 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 you are most likely to see when purchasing jewelry:

Round Cut The round cut is perhaps the most popular diamond cut sold today. This is the cut specifically designed to maximize brilliance. As a result, flaws and yellow tones are less visible in round-cut diamonds than in stones of other cuts. Many consumers consider the round cut to be 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're looking for a diamond that has a square or rectangular shape while still exhibiting a good amount of sparkle.

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

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

Radiant Cut The radiant cut has a rectangular or square shape with truncated corners. This is another brilliant cut that is often compared to the cushion cut. The radiant cut shares some characteristics that are characteristic of the emerald cut, and this commonality 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 the illusion 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 adequately protected by the setting when the diamond is mounted in a piece of jewelry.

Pear Cut: The pear cut has an oval shape with one of its ends pointed, giving the outline of this cut a teardrop or pear shape. 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 setting it 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 gap. 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 sharp, they can chip easily, so they should be protected accordingly when worn. Trillion-cut diamonds are often used as side stones, but can also be worn as center diamonds.