Diamonds: From Mine to Market What Is A Diamond? Click Here to Download As Word Document. A diamond is a crystal made up entirely of carbon atoms that are arranged in an isometric, or cubic, matrix. A cubic crystal arrangement is one in which the crystal essentially expands outward at the same rate in all directions during its initial growth; the ideal result, when the crystal forms without any interference, is a pure and perfectly formed octahedral shape. However, most diamond crystals encounter varying heat or pressure, other elements, or even other diamond crystals during their growth, and this can alter their form somewhat. The resulting form and characteristics of the crystal, once it emerges from the earth, help to determine what shape, color and clarity the polished gem will have. The combination of diamond's molecular composition and its crystal structure is what makes it so unique and gives it all the qualities that we think of when we think of a diamond. Consider this: The graphite that you commonly find in pencils is also made of pure carbon, but because the carbon atoms are arranged differently, the result is a soft gray-black substance that is very unlike hard, colorless diamond. And iron pyrite (known more commonly as "fool's gold") grows in an isometric arrangement, but because it is not made of pure carbon, it also lacks the spectacular qualities of diamond. The unique characteristics of diamond go far beyond what you can see with your eye. In addition to their superior brilliance and dispersion, diamonds are the hardest natural substance on earth. Diamond rates a 10 on the Mohs scale of hardness, which means that it is extremely resistant to scratches; it is several times harder than the next-hardest substance, corundum, which is more commonly known as ruby and sapphire. Diamonds are also very tough, meaning that they do not easily break, chip or crack. And even more interestingly, they are extremely resistant to heat and chemicals: it would take a temperature of at least 720° Celsius in air, or 850° Celsius in a vacuum, to burn a diamond; and sulphuric and hydrochloric acids, which are capable of completely dissolving the skin and bones of a person, have no effect at all on diamonds (in fact, these acids are actually used to clean the oil and dust off polished diamonds after they have been cut).

Where Does A Diamond Come From? Diamond is formed when carbon atoms deep in the earth are exposed to enormous heat and pressure over millions of years. In fact, the first known diamond deposits were brought to the surface of the earth two and a half billion years ago, and the most recent deposits are 50 million years, meaning that all diamonds are a genuine piece of pre-history! Diamonds made their journey from the asthenosphere (the layer of earth that lies 75 to 125 miles below the crust) to the surface when volcanic activity forced them, along with other rocks and minerals such as kimberlite, upward in a powerful explosion that formed a 'pipe' (a deep, wide opening in the earth). Once the diamonds and rocks shot upward, most of them fell back and settled into the pipes; when miners eventually discovered these pipes, they became known as 'primary deposits' of diamond. Other diamonds, though, were washed away either by erosion or by nearby waters; these formed deposits a distance away from the original source and they became known as 'alluvial deposits.' The first known source of diamonds was India, but now it is the countries of Australia, Botswana, Namibia, South Africa, Russia and Canada which produce as much as 80% of the world's diamonds. Diamonds are not at all easy to mine. In fact, more than 250 tons of ore need to be blasted, crushed and processed to yield just one carat of rough diamond! And of all the diamonds mined, only about 20% to 25% are gem-quality; the rest will eventually be used for technological and industrial purposes, or as abrasives. How Does A Diamond Get From Mines To Stores? Finding the rough diamonds is only the first step. Once diamonds have been mined and processed out of the 'overburden' (that is, the kimberlite rocks in which they are imbedded), the rough crystals are sorted and categorized according to their size, color, shape and other characteristics. At this point, a diamond can follow one of two routes: The most common route is through the channels of DeBeers' Central Selling Organization (CSO). Many people are familiar with DeBeers mainly because of their advertisements and commercials and because of the famous motto that they coined in the early half of the 20th century: "A Diamond is Forever." While DeBeers' market influence has decreased somewhat over the last few years, they still control the majority of the world's diamond production (an estimated 30% to 40% of annual diamond production). The purchasing arm of the CSO not only buys diamonds from member mines around the world; it also finances mining technology for governments which do not have the means to mine their own deposits. Most of what is bought through the CSO is sent to London to be offered to buyers through DeBeers marketing arm, the Diamond Trading Corporation (DTC). The DTC holds ten weeklong selling sessions called 'sights' each year. These sights are by invitation only, and only a handful of diamond manufacturers from around the world (called 'sight holders') are allowed to attend. These sight holders may chose to cut the rough diamonds they buy themselves, or they may chose to sell some of the rough diamonds to smaller manufacturers. These smaller manufacturers cut the rough diamonds and sell the polished gems either to jewelry manufacturers (who set the diamonds into finished pieces of jewelry and then sell the jewelry to jewelry retailers), or to diamond wholesalers (who then, in turn, sell the diamonds to diamond retailers). In the less common route from mine to market, some independent miners elect not to sell their mine production to the DeBeers cartel. Instead, they offer newly mined diamonds directly to other world buyers. These buyers, in turn, may chose to cut and sell the diamonds themselves, or pass the diamonds along within the industry in a manner similar to that described above.

Cut: Click Here to Download As Word Document. Diamond cut is perhaps the most important of the four Cs, so it is important to understand how this quality affects the properties and values of a diamond. A newly mined rough diamond looks more like a piece of glass washed up on the beach than like the polished gems sold in jewelry stores. Bringing out their beauty requires the skill and art of a trained diamond cutter. While incredibly precise, computerized machinery is now used in some parts of the cutting process for some diamonds, most of the work is still performed by hand using exacting and meticulous techniques passed down over the generations. As a first step, cleaving or sawing is often used to separate the original rough into smaller, more workable pieces that will each eventually become an individual polished gem. Next, bruiting grinds away the edges, providing the outline shape (for example, heart, oval or round) for the gem. Faceting is then done in two steps: during blocking, the table, culet, bezel and pavilion main facets are cut; afterward, the star, upper girdle and lower girdle facets are added. Once the fully faceted diamond has been inspected and improved, it is boiled in hydrochloric and sulfuric acids to remove dust and oil. The diamond is then considered a finished, polished gem. A good cut gives a diamond its brilliance, which is that brightness that seems to come from the very heart of a diamond. The angles and finish of any diamond are what determine its ability to handle light, which leads to brilliance. As you can see in the image 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.

Don't confuse diamond cut with shape. Shape refers to the general outward appearance of the diamond, not it's reflective qualities.

Good Proportions are Key

Most gemologists agree that the best-cut diamonds are those that follow a set of formulae calculated to maximize brilliance. These formulae can be seen in a diamond's proportions, most importantly how the depth compares to the diameter, and how the diameter of the table compares to the diameter of the diamond.
One of the leading diamond grading bodies, the AGS, has developed a table, which they believe offers the "ideal" proportions of diamond. The image below details the various parts of the diamond, together with the recommended proportions of the AGS.
Because cut is so important, several grading methods have been developed to help consumers determine the cut of a particular diamond. In general, these grades are Ideal, Excellent, Very Good, Good and Fair.

Diameter: The width of the diamond as measured through the girdle.
Table: This is the large, flat top facet of a diamond.
Crown: The upper portion of a cut gemstone, above the girdle.
Girdle: The narrow rim of a diamond that separates the crown from the pavilion. It is the largest diameter to any part of the stone
Pavilion: The lower portion of the diamond, below the girdle. It is sometimes referred to as the base.
Culet: The tiny facet on the pointed bottom of the pavilion, which is the portion of a cut gem below the girdle.
Depth: The height of a gemstone, from the culet to the table.

Which Grade or Cut Should I Buy?

Selecting the grade of cut is really a matter of preference. To make the best selection, you need to understand the various grades. Vummidi grades its diamonds as Ideal, Very Good, Good, Fair or Poor.

Ideal
Diamonds that are described by Vummidi as Ideal have a make, which is considered fine by anyone in the industry. This cut is intended to maximize brilliance, and the typically smaller table sizes of these diamonds have the added benefit of creating a great deal of dispersion or 'fire' as well. Ideal quality diamonds are truly for the person who enjoys knowing that he has one of the finest things that money can buy. This category applies only to round diamonds.

Premium
Diamonds that are described by Vummidi as Premium have a make, which is considered fine by anyone in the industry. In the case of round diamonds, many of these diamonds have cuts that are the equal of any Ideal Cut diamond, though they often can be purchased at slightly lower prices than AGS Ideal Cuts. They are intended to provide maximum brilliance and fire. They are truly for the person who enjoys knowing that he has one of the finest things that money can buy.

Very Good
Diamonds that are described by Vummidi as Very Good are of a excellent make. They reflect most of the light that enters them, creating a good deal of brilliance. With these diamonds, the cutters have chosen to stray slightly from the preferred diamond proportions in order to create a larger diamond. The result is that these diamonds fall slightly outside of some customers' preferences in terms of, for example, table size or girdle width, though, in many cases many of the parameters of diamonds in this range will overlap with certain parameters of diamonds in the Ideal or Premium ranges. Generally, the price of these diamonds in slightly below that of Premium cuts.

Diamond Clarity

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When we speak of a diamond's clarity, we are referring to the presence of identifying characteristics on and within the stone. While most of these characteristics are inherent qualities of the rough diamond and have been present since the earliest stages of the crystal's growth below ground, a few are actually a result of the harsh stress that a diamond undergoes during the cutting process itself. If you think about the incredible amount of pressure it takes to create a diamond, it's no surprise that many diamonds have inclusions-scratches, blemishes, air bubbles or non-diamond mineral material-on their surface or inside. Diamonds with no or few inclusions and blemishes are more highly valued than those with less clarity, not just because they are more pleasing to the eye, but also because they are rarer.

How Are Diamonds Graded for Clarity?

Diamonds are graded for clarity under 10x loupe magnification. Grades range from Internally Flawless, diamonds that are completely free of blemishes and inclusions even under 10x magnification, to Imperfect 3, diamonds, which possess large, heavy blemishes, and inclusions that are visible to the naked eye.

F-IF- Flawless or Internally Flawless, This diamond has no internal inclusions, Very rare.

VVS1-VVS2 - Very Slightly included, Minute inclusions very difficult to detect under 10x magnification.

VS1-VS2- Very Slightly included (two grades), Minute inclusions invisible to the naked eye and seen only with difficulty under 10x magnification.

SI1-SI2- Slightly Included (two grades), Minute inclusions very difficult to detect under 10x magnification.

I1-I2-I3- Included (three grades), Inclusions visible under 10x magnification as well as to the human eye.

While the presence of these clarity characteristics do lower the clarity grade, and therefore the value, of a diamond they can also be viewed as proof of a diamond's identity. GIA certificates include what is known as a "plot" of a diamond's inclusions. Since no two diamonds are exactly the same, comparing the uniqueness of your diamond's clarity characteristics with the plot provided on the diamond certificate offers assurance that the diamond you pay for is the same diamond you receive.

Which Clarity Grade Should I choose?

While Flawless diamonds are the most rare, and arguably the most beautiful diamonds, a diamond does not have to be completely clean to be extremely attractive. Those diamonds with VVS and VS grades can be excellent choices as well. More affordable are those diamonds which gemologists call "eye-clean" - diamonds with no inclusions visible to the naked eye. These diamonds are SI or SI2. The table below demonstrates the effect that clarity has on diamond pricing; assuming carat, cut and color remain the same.

Which Color Grade Should I Choose?

Diamonds graded D through F are naturally the most valuable and desirable because of their rarity. Such diamonds are a treat for the eyes of anyone. But you can still obtain very attractive diamonds that are graded slightly less than colorless. And diamonds graded G through I show virtually no color that is visible to the untrained eye. And while a very, very faint hint of yellow will be apparent in diamonds graded J through M, this color can often be minimized by carefully selecting the right jewelry in which to mount your diamond. Keep in mind that, while most people strive to buy the most colorless diamond they can afford, there are many people who actually prefer the warmer glow of lower-color diamonds. To ensure that our customers enjoy only fine, classic jewelry, Vummidi does not offer diamonds that have been graded below M.

What is Fluorescence?

Fluorescence is an effect that is seen in some gem-quality diamonds when they are exposed to long-wave ultraviolet light (such as the lighting frequently seen in dance clubs). Under most lighting conditions, this fluorescence is not detectable to the eye. While most gemologists prefer diamonds without this effect, some people enjoy it. It's really just a matter of aesthetics.

Carat Weight

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A carat is a unit of measurement, it's the unit used to weigh a diamond. One carat is equal to 200 milligrams, or 0.2 grams. The word carat is taken from the carob seeds that people once used in ancient times to balance scales. So uniform in shape and weight are these little seeds that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them. Don't confuse it with 'karat', the method of determining the purity of gold. The process that forms a diamond happens only in very rare circumstances, and typically the natural materials required are found only in small amounts. That means that larger diamonds are uncovered less often than smaller ones. Thus, large diamonds are rare and have a greater value per carat. For that reason, the price of a diamond raises proportionately to its size.

What Does A Carat Look Like?

The tool below demonstrates the relative size of a diamond set in a ring. Note that an increase in carat weight does not necessarily translate to a proportionate increase in the way it looks to the naked eye. A 2-carat diamond does not appear to be twice as a big as 1-carat diamond, especially if you look at it from the top.

Size

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What Size Diamond Should I Buy?

How important size is to you is probably contingent on how important it is to the person you're giving it to. A few tips to keep in mind will help guide you to the right decision. The general rule of thumb when buying a diamond is "two months salary". This is just a guideline, it's not carved in stone, but it's useful in establishing a budget for how much you can comfortably invest in her diamond · Deciding on carat size is really about striking a balance between size and quality. If she prefers larger jewelry items, and you are working within a budget, you can still find a larger diamond of excellent quality gem by selecting one, which is graded slightly lower in terms of color and clarity. · Remember that slender fingers make small diamonds look bigger. If she has small fingers, a 1-carat diamond will look proportionately large--and an even larger stone may appear stunningly big! · Think about what sort of setting will hold the diamond. You'll have to be sure that the setting you choose is made to fit the carat weight of your diamond.

Diamond Certificates

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A certificate is a "blueprint" of a diamond, it tells you the diamond's exact measurements and weight, as well as the details of its cut and quality. It precisely points out all the individual characteristics of the stone. Certificates also serve as proof of the diamond's identity and value. Note that a certificate is not the same thing as an appraisal. A certificate describes the quality of a diamond, but it does not place a monetary value on the gem.

Who Issues Certificates?

There are many diamond labs that issue certificates, but the Gemological Institute of America (GIA) and the American Gem Society (AGS) are the two most widely regarded and recognized diamond-grading labs in the world. All Vummidi diamonds featured in our Diamond Store are certified by one of these two labs.