Diamonds begin life as a lump of carbon; it was once like the lead in your pencil. But over billions of years the carbon crystalized — just as water crystalizes into a snowflake and sugar crystalizes into rock candy.
Each diamond forms differently and these are the terms used to describe the characteristics for each diamond:
- Shape, Size, Clarity, Color, Cut, Brightness, Fire, Sparkle, Polish, Symmetry, Fluorescence, Luster.
Raw diamonds, from the earth, are cut to different shapes. The shape refers to the pattern when viewed from the top. Choosing your shape is a matter of taste.
"Shape" and "cut" are often confused for one another but describe different characteristics of a diamond. Shape is the view from the top; cut is the view from the side.
The round shape, or sometimes called round-brilliant, is the most popular shape, followed by the square. The popularity of diamond shapes comes and goes, however round is classic and will stand the test of time, followed by square and cushion shapes. More unusual shapes only look proper in certain ring designs.
Diamonds are weighed in "carats" or "points" before to being set into jewelry. Carats and points are both units of measure, just like pounds or ounces. A "one carat diamond" is equal in weight to 1/5 of a gram.
Carat (spelled with a 'c') is often confused with karat (spelled with a 'k'), which is used when referring to the percentage of gold content in jewelry as in "fourteen-karat-gold".
A one carat diamond has 100 points — just like one dollar has 100 cents. So, for example, a 1/4 carat diamond is approximately 23 points to 28 points, and a 2 carat diamond is exactly or near 200 points, and so on.
Carat weight doesn’t always reflect size.
That's because the secret to unleashing the beauty from within a diamond, is to cut away valuable weight from the very bottom of the raw stone. And if this weight isn't trimmed off you end up paying for weight that doesn't make the diamond look larger and detracts from its beauty. Think of it like a butcher who sells you a steak without trimming the fat.It's the difference between quantity vs. quality. So compare diamonds by its diameter (or dimensions viewed from the top), not its weight.
How does size affect price?
The larger they are, the more costly per unit of weight.
A 1/2 carat diamond selling for $2000 would cost about $8400 if it were a one carat with identical characteristics.
Clarity describes the natural birthmarks that formed within the diamond and its surface imperfections that were not, or could not, be polished away as nature transformed carbon into a crystal. Think of clarity like a fingerprint. Every diamond is unique and can be identified by its natural markings even though it may require a microscope. These varied markings inside and on the surface of a diamond can look like black specks or lines, white specks or lines, bubbles, cracks, or clouds.
Do not select your diamond based on what you see under the microscope. Markings that are easy to see under a high quality microscope often times are not visible to the un-aided eye. View diamonds placed side-by-side next to the highest clarity available; in many cases, you will not see any difference even when examined at very close range without magnification.
Gemologists determine clarity by observing the size, location, quantity, type, and prominence of the “blemishes” in accordance with the GIA’s standards. Except for I1*, I2*, and I3*, and sometimes SI2*, clarity does not determine the diamond's beauty; clarity's purpose is to group the diamond according to its rarity. Do not select your diamond by selecting a particular clarity grade. Two diamonds of the same grade may not look the same. A "high" SI1 has a very different value than a "low" SI1.
Diamonds form in different colors. Don't think of these colors as red-like-a-ruby or blue-like-a-a-sapphire. These differences in color are very subtle. Color is more like the difference between crystal clear spring water and lemonade. Some diamonds lack any tint or body tone and are clear as icy spring water. These icy "white" diamonds provide the perfect backdrop for displaying the inner blaze that result from a diamond’s unique optical properties. Other diamonds with varying tinges of yellow (or brown or grey) look as if a glass of water had drops of lemon squeezed in until it became lemonade; this added color mutes the powerful inner-blaze.
Of course, the whiter ones are brighter. But keep squeezing in lemon until the diamond becomes intense yellow like the sun, then they become more valuable than the whitest ones. That's because when they're super-saturated with color, they're much scarcer than icy white ones, and classified as fancy-colored.
With fancy colors, the intensity of the color is just as important as the brightness of the diamond.
Purchase the highest color as you can afford in the size you're hoping for. "High color" really mean "absence-of-color" since the best color is no color at all. Color, or body-tones, are usually yellow but can also be brown or grey. "Color" means something completely different, yet interactive with, "fire", which comes from a diamond's unique ability to bend light like a prism producing brief inner flashes of reds, blues, and greens.
The highest grade in the GIA scale is "D color" all the way down to "Z". The reason it begins with "D" instead of "A" was to avoid confusion with the many competing color-grading scales that were already in existence prior to 1953 when the GIA introduced its system. Gemologists compare each diamond, placed upside down on its table (top surface), to a set of master comparison diamonds in a predetermined standard lighting and viewing environment to determine its color.
Cut describes the workmanship and design of turning a "raw" diamond from the earth, into a vibrant gemstone. How a diamond is cut, or designed, determines its Brightness, Fire, and Sparkle and all three characteristics are incorporated in the cut grade. Distinguishing these three different characteristics of how light interacts with a diamond is easy when viewing diamonds side by side. Choosing the characteristics that are most pleasing to you is about your taste and what pleases your eye. You may prefer a diamond with a cut grade of Very Good over one graded Excellent –and that’s ok. Diamonds with a cut grade of Good, Fair, and Poor are not pleasing to most people.
Brightness, sometimes called brilliance, is the level of light that radiates up from within and off the surface of the diamond. When a ray of light passes through the surface of a diamond, it will bend like a light ray passing through a prism. But with diamonds, light bends even more because they are so dense. Once inside the diamond, as the light ray continues on its path, it will bend two more times completing a U-turn so that the light ray returns a shower of brightness and fire back toward your eye but only if cut with a proper silhouette. Without a proper silhouette, light will bend upon entering the diamond’s surface, but some light will escape through the side and bottom of the diamond and fail to complete the U-turn, causing less brightness and less of the rainbow-like fire that results from each bend.
Why don't all diamonds have a desirable silhouette? This is the secret to what is called weight-ratio. Weight–ratio is the relationship between the diamond size (viewed from the top) and its weight. Almost all raw diamonds come from the earth with a silhouette that is too deep. Think of the diamond cutter like a butcher who must trim away fat. An example might be if a raw diamond, cut to a round shape, has a diameter of only 6 mm then its proper design would be as a ⅞ carat with a lean under-belly and a proper silhouette. If the underbelly "fat" were not removed, the 6 mm diamond would have the wrong weight-ratio. It will weigh one carat but will look like a ⅞ carat diamond lacking beauty. In most cases, in order to unleash a high level of brightness the cutter must slice away slabs from its "belly", to steer light in a desirable U-turn
Fire, sometimes called dispersion, describes the colors-of-a-rainbow that appear in a diamond. Diamonds behave like prisms. Since its shape is different than prisms the colors don’t appear in straight rows but more like shards of color as in a kaleidoscope. As a diamond moves the shards of colors change like in a kaleidoscope, so it’s best to see fire in different lighting conditions, from different viewing angles. It is also best to view the diamond from a distance of over three feet because when viewed from up close the chards of color change to shards of white light.
Sparkle, also called scintillation, describes the twinkling effect given off as diamonds move about, as if there are white flashes of fireworks within the diamond. The sparkle, or flashes-of-light, comes from rays of light reflecting off the diamond’s many surfaces. Your eyes "notice", or perceive, the flashes if there is sufficient contrast of dark areas within the diamond just as stars against the dark night are lost in the daytime. All diamonds will have some amount of these flashes however multiple mini-flashes are more beautiful than one big blast blaring like a headlight. The pattern of sparkle should be an evenly spread out field of "stars" rather than a blotchy array.
Polish describes the quality of a diamond's surface. Imagine a typical diamond's many polished surfaces, called facets. Their shapes vary but most resemble either a triangle or a stretched or contorted kite. And, due to a diamond's extreme hardness, creating a mirror-like finish on each surface can only be achieved after long and painstaking grinding then polishing. Why is this important? Because even if it takes a microscope to see the tell-tale parallel or circular lines that result from an improperly polished diamond, if not eliminated, they will interfere with the luster, or "pop", that comes from light reflecting off its surfaces. Then, these individual surfaces must join invisibly, with seamless edges, so that the diamond appears as a solid monolith. Finish is important but a grade of Very Good may result from "deductions" that are visible under a microscope but do not affect the visual beauty of the diamond.
Symmetry describes the alignment of the many surfaces on a diamond, called facets. Diamonds that are perfectly aligned appear more beautiful to us. Symmetry also describes how perfect the shape of diamond is. For instance, if the diamond is supposed to be round, is there a flat spot along the circle or a perceptible oval shape to the circle? The workmanship involved in creating excellent symmetry takes time, care, planning & attention to detail. The GIA symmetry grades are Excellent, Very Good, Good, Fair, and Poor. Trust your eye and your judgment. Don't get too hung up on a grade of Good or Very Good because there can be symmetry "deductions" that are visible under a microscope that do not affect the visual beauty of the diamond.
Fluorescence is the "glow-in-the-dark" effect some diamonds emit when they are exposed to invisible ultraviolet (UV) rays. The sun emits UV rays. Grading reports measure the strength, or intensity, of the diamond's fluorescent tendencies but do not address whether the diamond's beauty is affected.
For almost all fluorescence diamonds with faint fluorescence, its fluorescence does not affect its beauty; when a diamond has medium in fluorescence, it's beauty can be affected. For diamonds with strong or very strong fluorescence it's important to view the diamond in strong sunlight because it may appear hazy or oily and undesirable. The price of diamonds are lower the more fluorescence it exhibits.
Diamond is the hardest material in the world but that doesn’t mean you can't break or chip it. The definition of "hardness" is the resistance to scratching. In fact, when a diamond cutter splits a raw diamond crystal into two pieces often times all it takes is a tap in the right spot. It is important to cut a diamond so that its outer edge, called its girdle, is not too thin. Otherwise, over time, the girdle may be exposed and susceptible to getting chips. Equally important is the tiny facet called the 'culet', that looks as if it's a point that is on the very bottom of the diamond. Under a microscope you'll notice that some diamonds don’t have the culet and actually do come to a point. Polishing a diamond without a culet is a signature of a diamond cutter's expertise, though this type of diamond must be handled by expert diamond setters, so the point is not damaged. Also, the corners of certain shaped diamonds come to a point requiring the skills of highly experienced diamond setter when secured into a ring.
Diamonds have an important quality characteristic that is not included on diamond certificates called luster. This characteristic describes the "pop" of the diamond. Differences in luster are due to way the crystal structure formed. An analogy is to think of two pieces of maple wood where one has smooth even grain and another has knots with wavy grain. Diamonds that have a poorer crystal structure will appear as a dull, oily, or greyish. A diamond can have a respectable grade but be missing "the bling". A proper crystal structure will result in a vibrant, powerfully brilliant stone. The only way to insure that your diamond has excellent luster is by viewing the diamond. You cannot determine the luster from a certificate or an online image.