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Choosing a shape • The Four C's • The basic parts of a cut diamond • What makes a diamond sparkle
A diamond, although just a stone, is the hardest substance on earth and has for centuries intrigued and awed people. Not in its raw form, though, but in it's cut and polished splendor. Diamond is the crystallized form of carbon. Carbon crystalises in a cubinc system which is the strongest and most symmetrical known on Earth, and is born hundreds of miles below the Earth's surface. Diamonds were formed more than 70 million years ago when diamond-bearing ore was brought to the surface through volcanic eruption. After the magma cooled, it solidified into blue ground, or kimberlite, where the precious rough is found today. The durability of a gem depends on both its hardness and toughness. Diamond, although highest on the scale of hardness (rated 10 on the Mohs scale), is not as tough as some gems because of its good cleavage. (Cleavage is the tendency of a diamond to split in certain directions where the carbon atoms are furthest apart.) Diamonds have a very high degree of transparency, refractivity and dispersion or 'fire' which gives rise in cut diamonds to a high degree of brilliancy and a display of prismatic colors. A diamond's fiery brilliance makes it cherished above all other gemstones by the majority of people. Diamonds occupy a position of incomparable demand.
The word alone conjures up a shundreds of images: rare, precious, desirable, beautiful, sparkling tokens of love. Created deep within the core of the earth and brought to the surface by volcanic eruption, most of the diamonds sparkling on fingers today are more than 100 million years old! Even before these magnificent creations of nature were mined in profusion toward the end of the 19th century, they were a source of fascination and value to early man. The Romans thought diamonds were splinters from falling stars, while the Greeks regarded the sparkling gems as tears of the gods. It is a derivation of the Greek word "adamas," meaning unconquerable, that gave the diamond its name.
The diamond claimed its place as the primary token of love toward the end of the 15th century, when Austrian Archduke Maximilian gave the first diamond engagement ring to his betrothed. It was placed on the fourth finger of her left hand, because that finger was believed to course with the vein of love that passed directly to the heart. Five centuries later, the diamond remains one of the most luxurious and desirable gifts for any romantic and celebratory occasion, a gem whose purity and brilliance symbolizes lasting love. But, what Makes a Diamond Special? Beauty: The colorless beauty and inner fire of the diamond has made this precious gem prized for centuries. Each stone's complex characteristics cannot be duplicated, and no two diamonds can ever be the same. Each stone, like its owner, is endowed with a personality and character uniquely its own. Durability: A diamond is the hardest substance known to man, making it resistant to deterioration. When cared for properly, diamond jewelry can be worn every day and passed on as an heirloom to the next generation. Rarity: Although new resources for diamonds are being explored and discovered, the supply of these gems remains limited. This is understandable once you learn that more than 250 tons of ore need to be blasted, crushed and processed to yield just one carat of rough diamond. Further, only 20 percent of all rough diamonds are suitable for gem cutting. Enduring Value: Like many precious products, diamond prices fluctuate. But it is important to know that these sparkling gemstones still retain value after years of being worn and enjoyed.
The most traditional shape is the round brilliant diamond. This is the choice of many and the first image that comes to mind when diamonds and diamond rings come to mind. Only the masterful skill of the diamond cutter can attempt the transformation that the raw diamond crystal goes through. From raw material to incredible and unique.
Round Brilliant This is the shape that has set the traditional standard for all diamond shapes. Over 75% of the diamonds sold today are Round Brilliant. Its 58-facet cut, divided among its crown (top), girdle (widest part) and pavilion (base), is calibrated through a precise formula to achieve the maximum in fire and brilliance.
Oval This is a symmetrical design which is even and appeals to many small handed women seemingly elongating hands and fingers.
Marquise This shape is elongated with pointed ends. The smile of the Marquise de Pompadour inspired this shape which was then commissioned by the Sun King, France's Louis XIV, who wanted a diamond to match it. It is beautiful as a solitaire or when matched with smaller complimentary diamonds.
Pear This cut combines the oval and marquise shapes. It is the hybrid shape that looks like a sparkling teardrop. It beautifully compliments the average size hand and fingers. It is gorgeous for pendants and earrings.
Heart A pear shaped diamond with a cleft on the top. The extraordinary skill of the cutter determines the beauty of this cut. Look for a stone with an even shape and a well-defined outline.
Emerald This shape is known as a step cut because its concentric broad, flat planes resemble stair steps. A rectangular shape with cut corners. Inclusions and inferior color can be more pronounced in this particular cut. So clarity and color should be looked at carefully and time taken when a choice is made.
Princess This is a square or rectangular shape with many facets. This is a relatively new cut and often finds its way into solitaire engagement rings. It is attractive with longer fingers. This cut requires more weight to be directed toward the diamond's depth in order to maximize brilliance. Depth percentages of 70% to 78% are common.
Trilliant This is the spectacular wedge shape. This was first designed in Amsterdam. This design can vary depending on a particular diamond's natural characteristics and the cutter's personal preferences. The shape may look like a traditional triangle with pointed corners, but more rounded shapes can be found.
Radiant This is a square or rectangular shape. The elegance of the emerald and the brilliance of the round shape marks this cut. 70 facets maximize the effect of its color refraction. Depth percentages of 70% to 78% are common.
Cushion Cut Late 19th and early 20th style antique type shape. Remnants of the "Old Mine Cut", a deep cut with large facets.
Asscher Cut This cut was made popular in the 1920's by the Asscher Diamond Company in Amsterdam. Its art deco feeling was very popular at the time. The company went out of business during the Depression and Asscher cuts disappeared from the market. Recently this shape has come back into style.
Before you start looking for a diamond, you want to have all of the necessary information that is available to you, because the more you know, the better prepared you are to make decisions regarding your purchase.
Diamond cut Most diamonds are cut round with a full 58 facets, and a good cut, or make, has more scintillation, more sparkle. It is the work of a master cutter that allows the diamond to be cut in such a way as to permit the maximum amount of light to be reflected through the diamond, and that's a great reflection on you. It is the cut that enables a diamond to make the best use of light.
Color grading
As you can see the color-grading scale ranges from D to Z. The highest color grade and whitest stone available is a D color diamond. This is also the rarest color grade, which translates to a higher value. Colors E and F have no detectable color to the naked eye and they fall into the Colorless category. Diamonds in the G to J color range have a hint of body color and are considered Near Colorless. The eye begins to detect faint traces of yellow in diamonds that are in the J to M range. The AGSL (American Gem Society Lab) uses a slightly different color grading scale. The AGSL ranks the stones from 0-10, in 0.5 increments with 0 representing the equivalent of colorless D stones, and 10 representing the equivalent of X, Y and Z colored diamonds. Ideal Cut diamonds offer a little flexibility in color selection. Because Ideal Cut diamonds are designed to maximize brilliance and scintillation they also tend to mask subtle color differences making H and I color diamonds appear beautifully white. Ideal Cut H and I color diamonds tend to appear whiter than poorly cut diamonds of the same color.
Clarity The diamond's clarity is a description of its internal purity. With fewer imperfections within the stone, the diamond is more rare and has a higher value. The clarity scale was developed by the Gemological Institute of America (GIA) to quantify these imperfections. The American Gem Society (AGS) uses the same standards as the GIA; however, the AGS uses a numerical system where "0" is the cleanest (GIA "IF") and "10" is the most imperfect (GIA "I3"). All diamonds are systematically graded and plotted under 10X magnification. If a trained grader cannot see a clarity characteristic at 10X, it does not affect the clarity grade. Five Factors That Determine Clarity: size, number, position, nature, color. All of the above factors are taken into consideration when a diamond is assigned a clarity grade. The GIA defines Clarity Grades as follows:
Internally Flawless (IF) — An IF diamond has no inclusions, only blemishes when viewed under 10X magnification. Very Very Slightly Included (VVS1 and VVS2) — VVS diamonds contain minute inclusions that are difficult for a skilled grader to see under 10X magnification. The inclusion in a VVS1 diamond are extremely difficult to see face-up, or may be visible only through the pavilion. Inclusions in a VVS2 diamond are very difficult to see. Typically VVS diamonds have a pinpoint or two; however, characteristics like a bearded girdle or tiny chips might also be present in VVS diamonds depending on their visibility. Very Slightly Included (VS1 and VS2) — Diamonds of VS clarity contain minor inclusions that range from difficult (VS1) to somewhat easy (VS2) to see under 10X magnification. Typical inclusions in VS diamonds include small crystals, feathers and distinct groups of pinpoints. Slightly Included (SI1 and SI2) — Diamonds of SI clarity contain noticeable inclusions that are easy (SI1) or very easy (SI2) to see under 10X magnification. Typical inclusions, such as crystals, clusters of pinpoints and feathers, are centrally located. Included (I1, I2, and I3) — Diamonds in the 'I' clarity range contain inclusions that are obvious under 10X magnification. These inclusions can often times be seen face-up without magnification, sometimes affect the stone's durability and can be so numerous or large that they affect transparency and brilliance. The clarity is typically assigned by a first impression or at first glance. The grader notes whether the inclusions are easy, difficult or very difficult to see when they first look at the stone. The clarity grade of most diamonds is determined in less than 2 minutes. The exception to this is in Internally Flawless and Flawless diamonds, which take considerable examination to assign such a high and valuable grade. It of course takes longer to plot included diamonds as well. "Eye-clean" is a term used to describe a diamond or an inclusion that is not visible to the unaided eye when the diamond is held face-up (viewed through the table) at a normal viewing distance of 10 to 12 inches. Nearly all VS clarity diamonds are eye-clean, most SI1 clarity diamonds are eye-clean and some SI2 and even I1 clarity diamonds are eye-clean. An inclusion is called "eye-visible" when it is visible to the unaided eye, without magnification.
There are two basic categories of clarity characteristics, inclusions and blemishes. Inclusions are clarity characteristics that are completely enclosed in a polished gem or those extending into it from the surface. Examples of inclusions are as follows: Crystal — Another mineral crystal contained in the diamond. These crystals can include other diamonds, garnet or a host of other minerals. Needle — A long, thin crystal. Pinpoint — A very tiny crystal that looks like a dot or speck of dust. Pinpoints often congregate in clusters or clouds. Twinning wisp — A series of pinpoints, clusters or crystals that formed in a twinned diamond's growth plane. Internal graining — The appearance of faint lines, angles or curves caused by crystal growth. Feather or gletz — A general term for any break or fracture in a diamond. Bearded girdle — Minute feathers that extend from the girdle surface into the stone. Indented Natural — The original crystal surface, or skin, that dips below the polished diamond's surface. Knot — An included diamond crystal that extends to the surface after polishing. Cavity — Space left when a surface-reaching crystal comes out during polishing. Blemishes are external clarity characteristics caused by wear, the cutting process or the diamonds crystal structure. Examples of blemishes are as follows: Nick — A small chip-like characteristic. Abrasion — A series of minute nicks along a facet junction. Scratch — A thin, dull, white line across the diamond's surface. Natural — A portion of the original skin that remains on the diamond. Pit — Small surface characteristic that looks like a tiny dot.
Clarity enhancement is a treatment to improve a diamond's apparent clarity. A diamond with eye-visible inclusions can be seen as less desirable. To make the diamond more desirable and marketable, some sales people have the diamond clarity enhanced to make the eye-visible inclusions less visible or invisible to the naked eye. There are two common types of clarity enhancement. The first type of clarity enhancement is called laser drilling. Laser drilling is the use of a laser to drill a small hole in the diamond, extending to reach a visible inclusion such as a black crystal. Sometimes an acid is used to bleach or dissolve the included color, improving its appearance. Laser drill holes can typically be seen as tube like inclusions in the diamond when viewed perpendicular to the point of entry under 10X magnification. The hole can also be seen as a tiny pit-like blemish on the surface, under reflective light of a microscope. The second type of clarity enhancement is fracture filling. Fracture filling involves the use of a molten glass substance to fill or mask the reflective qualities of an internal fracture. Fracture filling can be detected by the telltale 'flash effect' that the filling produced. The flash effect can be seen as two distinctly different colors that appear when you rock and tilt the diamond in different directions. Some untreated feathers can show an iridescent rainbow of colors from all directions, so it is important to know the differences. Fracture filling is not a permanent treatment and therefore GIA does not grade fracture filled diamonds. GIA does, however, grade the permanent laser drilled diamonds.
Carat Weight A carat is a weight measuring unit equal to 0.2 grams. It is the internationally used unit to measure the weight of diamonds. Within the diamond trade, fractions of a carat are referred to as "points" or simply as fractions. A 50-point diamond weighs 0.5 carats or 1/2 a carat. A 1-carat diamond weighs 100 points. A 1/3 is also 0.3 carats or 30 points. As nature would have it, rough diamonds come in all shapes and sizes, as well as colors and purities. The larger, whiter and cleaner the diamond, the more rare it is. Accordingly, the cost per carat of a larger diamond of the same color, clarity and cut will be higher than a smaller diamond. The price per carat of diamonds rises proportionately with size. Keep in mind that the per carat price gets multiplied by the carat weight. More weight equals more money so, many diamond cutters sacrifice brilliance to maximize carat weight and profit. It is important to realize that weight does not always equal size or beauty. Poorly cut diamonds intended to maximize size can be dull and lifeless. Some experienced cutters sacrifice weight and focus on cut to obtain the most beautiful and brilliant Hearts and Arrows diamonds on the market today. On the average, cutting a Hearts and Arrows Ideal Cut Diamond requires a 15% greater waste of the original material. The added beauty one obtains from a Hearts and Arrows diamond is well worth the sacrifice.
The basic parts of a cut diamond
Crown: The upper part of the diamond above the girdle. Consists of a large flat area on top called a table, and several facets below it Girdle: The outer edge or the widest part of the diamond forming a band around the stone. Pavilion: The bottom part of the Diamond, below the girdle. Culet: A tiny flat facet that diamond cutters sometimes add at the bottom of a diamond's pavilion. Its purpose is to protect the tip of the pavilion from being chipped or damaged. Once a diamond is set in jewelry, though, the setting itself generally provides the pavilion with sufficient protection from impact or wear. Large or extremely large culets were common in diamonds cut in the early part of this century, such as the Old European or Old Mine Cut. However, such large culets are rarely seen today. Most modern shapes have either no culet at all, or a small or very small culet. Depth: The height of a diamond from the culet to the table. The depth is measured in millimeters. Crown angle: The angle at which a diamond's bezel facets intersect the girdle plane. This gentle slope of the facets that surround the table is what helps to create the dispersion, or fire, in a diamond. White light entering at the different angles in broken up into its spectral hues, creating a beautiful play of color inside the diamond. The crown angle also helps to enhance the brilliance of a diamond. Table percentage: The value which represents how the diameter of the table facet compares to the diameter of the entire diamond. So, a diamond with a 60% table has a table which is 60% as wide as the diamond's outline. For a round diamond, gemologists calculate table percentage by dividing the diameter of the table, which is measured in millimeters (this millimeter measurement does not appear on diamond grading reports) by the average girdle diameter. For a fancy shape diamond, table percentage is calculated by dividing the width of the table, at the widest part of the diamond, by the millimeter width of the entire stone. Facet: The smooth, flat faces on the surface of a diamond. They allow light to both enter a diamond and reflect off its surface at different angles, creating the wonderful play of color and light for which diamonds are famous. The table below shows all the facets on a round brilliant cut diamond. A round brilliant has 58 facets (or 57 if there is no culet). Symmetry: Refers to variations in a diamond's symmetry. The small variations can include misalignment of facets or facets that fail to point correctly to the girdle. Symmetry is regarded as an indicator of the quality of as diamond's cut; it is graded as either Ideal, Excellent, Very Good, Good, Fair or Poor. Fluorescence: 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 night clubs). Under most lighting conditions, this fluorescence is not detectable to the eye. However, if a diamond is naturally fluorescent, it will emit a soft colored glow when held under an ultraviolet lamp or "black light." Fluorescence is not dangerous to the diamond or to the wearer; it is a unique and fascinating quality that occurs naturally in a number of gems and minerals. Most commonly diamonds fluoresce blue, but can also fluoresce yellow or white depending on which trace elements are found in the matrix of the diamond crystal. Fluorescence is described as none (or inert), faint, negligible, medium, strong and very strong. Fluorescence in diamonds can have both favorable and undesirable effects. For example, diamonds in the color range of I to N with medium to strong blue fluorescence can appear more colorless, which is an obvious advantage. The blue acts to mask or offset the very faint body color of these diamonds. On the other hand, diamonds with very strong fluorescence can exhibit an oily or milky appearance, even under incandescent lighting. However, according to a GIA study, the average observer could not detect any difference in color or transparency when viewing diamonds with fluorescence.
Brilliance is an essential attribute of a beautiful diamond and has 2 components; brightness and contrast. Bright diamonds return lots of light from the surroundings back to a 'face up' an observer. If light from above leaks out the back of a diamond, naturally it has less brightness. But light that enters and leaves in the face up direction is wasted because your head blocks the lights. Diamonds that are too deep or very shallow do this -they have areas that act like a mirror back to the viewer; they return less light and so they have less brightness. To be brilliant, a diamond needs more than just brightness. Consider the contrast of a chess board, although it has only 1/2 the light return of a sheet of white paper, it appears brighter, especially when it is moved because it 'scintillates'. Fire or dispersed light appears as flashes of rainbow colors. You see more fire in darker environments like restaurants that have just a few point light sources or just a flickering candle. Fire is also a result of a diamond's symmetry and proportions. There are several factors that greatly influence the amount of fire a diamond produces such as star facet length, lower girdle facet length, pavilion angle, facet junctions, the angle at which light enters the diamond, and the angle of the light rays as they exit the diamond. Diamond experts have known for a long time that steep crown angles and small tables (like 'old cut' diamonds) produce more fire. But this combination also produces less light return. Less light return makes it easier to see fiery flashes that might otherwise be swamped by bright white sparkles; that one reason is why old cut diamonds and some fancy cuts appear to have a lot of fire. Scintillation is the intense sparkles in a diamond as it moves. Black and white sparkles of scintillation show well in flood lit or office lighting environments where fire can be totally absent. Under pin point or spot lights fire also adds to scintillation. Ideally a diamond has many pleasing flashes spread across the surface of the stone, with few dull dead patches. Polish is graded the same way as symmetry: Ideal, Excellent, Very Good, Good, Fair or Poor on a GIA report. Poorly polished facets may reduce the intensity of light reflected from, or refracted into and out of, a diamond. Labs assess polish by examining the diamond, facet by facet, with reflected light under a microscope; you or I may not see any difference.
(source of the article is the website www.diamondideals.com where you can find much more of what you want to know about buying diamonds) |
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| Play the Life! creation - 2005 mail: creation - 2005 mail: creation - 2005 mail: creation - 2005 mail: info@playthelife.com | |||||||
The
most common diamond color is yellow. Most diamonds have a slight hint
of yellow and the diamond color scale is based on the amount of yellow
present in a diamond. Diamond color is graded according to the GIA
Grading Scale. Grades are based on the amount of yellow that is visible
when viewed facedown through the pavilion on a white diamond color card
using daylight equivalent fluorescent light. Each color grade is based
on a very small range. When a diamond is color graded it is compared
using a set of master stones. Master stones are a set of real diamonds
that display a range of known colors. It is extremely difficult to see
the color differences within diamonds, but master stones help graders
distinguish between one color and the next.
A diamond's color grade
does not pertain to the "face-up" look of a particular diamond, but
rather to the "body" color of the material. The best way to assess
diamond color is to view it from the side, un-mounted, against a white
background, using a daylight fluorescent bulb. An AGS Triple Ideal Cut
Hearts & Arrows diamond reflects more than 99% of the light back
through the crown. There is virtually no light leakage in these stones.
What this means to you is that rather than seeing the diamond's color,
when you look at a Hearts & Arrows diamond, all you see is white light
and scintillation. These diamonds appear whiter than non-Ideal
diamonds. Keep this in mind if budget is an issue. By dropping one
color grade in an AGS Triple Ideal Cut Hearts & Arrows diamond, you
will not be giving up anything in the look of your diamond and you will
be saving money.
Flawless
— Flawless diamonds have no inclusions or blemishes when viewed under
10X magnification by a skilled grader. A diamond can have naturals
confined to the width of the girdle, extra facets on the pavilion that
are not visible face-up, laser inscriptions confined to the girdle and
internal graining that is not white, colored or reflective.
Table:
The flat facet on the top of the diamond. It is the largest facet on a
cut diamond.
Every
facet in an AGS Ideal Cut diamond must be placed at precise angles and
contain precise proportions. This ensures an Ideal balance between
maximum brilliance and dispersion of light. Any discrepancy from these
proportions will disrupt the even distribution and dispersion of light
within the stone, resulting in a loss of sparkle.A
well-proportioned pavilion is especially important to a diamond's
brilliance. Brilliance is the brightness created by the combination of
all the white light reflections from the surface and the inside of a
polished diamond. If the pavilion is too deep or too shallow, it causes
light to strike outside the critical angle - the largest angle at which
light rays inside the diamond can escape - causing the light to exit
through the pavilion rather than reflecting back to the eye as
brilliance.