Clarity : When looking at clarity, many diamonds have what are known as inclusions. These are scratches, tiny characteristics or trace minerals that can detract from the diamond's beauty. Clear diamonds are the most sought after and also the most expensive. Ratings for clarity will usually include flawless; very, very slightly included, with flaws which are very difficult to see and so on. Included diamonds, in which the flaws may be noticeable to the unaided human eye, are the lowest grade. Excessive inclusions or fractures not only make the diamond unattractive, but may weaken its strength so it is more likely to crack. However, flawless diamonds are extremely rare in nature. Some experts point out that no two diamonds are alike, and that inclusions in a particular stone are like its fingerprint, identifying it among all others.
Clarity Grading Levels:
There are 10 grading levels accepted Internationally in Diamond Clarity. Other qualities being equal, the lower the clarity grade, the less valuable the stone.
- IF - Internally Flawless
Free of flaws, cracks, spots, clouds, or any other blemish or imperfection of any sort when examined under proper light by a trained eye with the aid of a diamond eye loupe or other magnifier with a magnification of at least 10 power. - VVS1- Very, Very Slightly Imperfect (1)
The gem may have a very tiny pinpoint of included material, cloud, polishing line, or faint knot line, but only one of these blemishes and it is very faint to a trained eye under 10X magnification. Inclusions may be the same as for VVS1, but slightly larger and more numerous. They are still very hard to see. - VS1 - Very Slightly Imperfect (1)
The gem may have minute internal cleavage or fracture (feather) near the girdle, or it may have any of the above blemishes, slightly larger but still fairly difficult to detect under 10X magnification. - VS2 - Very Slightly Imperfect (2)
Any of the above inclusions are more easily visible under a 10X loupe. An included crystal or other small blemish may be seen through the crown. - SI1 - Slightly Imperfect (1)
The diamond has a cleavage fracture or any blemish or combination of blemishes not visible to the unaided eye but easily seen under 10X magnification. A small dark spot in the center of the stone or a larger white flaw toward the edge would be graded SI. - SI2 - Slightly Imperfect (2)
The diamond has slightly larger inclusions than grade SI1, but they still are not visible to the naked eye when the stone is face up. (NOTE: There is no such thing as a GIA grade of SI3. Such a stone is really just an I1 grade.) - I1 - Imperfect (1)
Inclusions are just visible to the eye without a loupe. - I2 - Imperfect (2)
Inclusions are easily seen with the unaided eye. - I3 - Imperfect (3)
This grade denotes a badly flawed diamond with cleavages, fractures, large clouds, and dark spots large enough to block light passage and destroy brilliancy. This grade of diamond would be inappropriate for jewelry.
Buying Tips & Suggestions:
- Diamonds often undergo treatments to conceal fractures and improve clarity. Since they may disguise a lower quality gem, diamond treatments should always be disclosed. "
- Clarity enhancements" are diamond treatments that improve the appearance of the stone (to the naked eye). Read about gem treatments to understand their purposes and their shortcomings before you shop for jewelry.
- When pricing diamonds, ask about gem treatments. When making a purchase, be sure to get in writing either that the gem is untreated or that it has been subjected to specifically named treatments, such as laser drilling or fracture filling.
Cut of the diamond will determine its brilliance and sparkle. The depth and width of the cut effects how light travels within the diamond. If the cut is too deep or too shallow, light will escape, causing a loss of brilliance. Polish and symmetry are also two important factors to be aware of. Gemologists consider the cut to be the most important factor, because even if the stone has perfect color and clarity, a poor cut will affect its brilliance.
Cut is the most important of the 4 Cs. It accounts for one half of the value of the diamond:
Cut is the most misunderstood of the 4 Cs. It is often wrongly thought of as the shape of the stone. This confusion exists because, of course, the raw material must be cut into a shape, and the confusion increases because shapes of diamonds are given names like Round Brilliant Cut, Oval Cut, Emerald Cut, and so forth.
Cut, when speaking of one of the four qualities that give diamonds their value, actually refers to the geometric proportions of the gem. The geometric proportions are important because a diamond is a prism that refracts, or bends, light rays, breaking white light into the colors of the rainbow. It is this refraction that unleashes the color spectrum in a way that gives a diamond its fire. The optical proportions must be exact in order to achieve maximum brilliance.
Light Refraction: Light enters from the top of the diamond, is funneled downward where it strikes facets at the bottom, then is refracted to other facets of the stone again and again as it works its way back up, until it leaves the stone at the top and enters the eye of the observer. Cutting proportions are extremely precise to achieve the best effect.
Proper Proportion : Many stone cuts lack proper proportion and refraction of light. The cut may be too heavy or too deep, allowing light to escape through the lower pavilion. If the cut is too shallow, light rays leak away at the bottom. Too much weight above or below the girdle affects the brilliance, and the stone lacks fire. Left illustration shows two well proportioned gems cut from diamond rough. At right, the same piece of rough could yield two larger stones (greater carat weight), but they would be poorly proportioned and much less attractive.
Cut and durability: The cut also affects the durability of the stone. The culet, the cut at the bottom of the diamond, is meant to flatten the point that would otherwise be vulnerable to chipping. If the culet is not present, or is too small, the stone will chip more easily. The girdle is where the setting holds the stone. If the girdle is too thin, the diamond will chip there. If the girdle is unevenly cut, the stone will be problematic to set. The cutting grade of a diamond is determined by analyzing the proportions and symmetry through the use of instrumented and/or visual techniques. Deductions are applied for departures from the standards for table diameter, crown angle, girdle thickness, pavilion depth, culet size and centering, roundness, and finish.
Buying Tips & Suggestions:
- Cut, which so affects the beauty of the diamond, plays an important part in determining its value. Two finished diamonds, equal in all respects except cutting proportions, can vary as much as 50 percent in price.
- When you ask the jeweler about the cut of a diamond, the name of a shape (such as "round brilliant cut") is irrelevant. You want the geometric proportions: table diameter, crown angle, girdle thickness, pavilion depth, and culet size.
Color : Diamonds can act as prisms, dividing light into a spectrum of colors. Diamonds with very little color are very highly valued. The less color, the more colorful the prism will become. A little color can diminish the diamond's value.
Color is usually given a rating. Absolutely colorless diamonds are at the top of the scale. These are extremely rare and are the highest color grade. The finest and most expensive diamonds are totally without color, like a drop of distilled water. The rainbow hues a diamond flashes derive from the light it separates into the colors of a spectrum. Diamonds of lesser quality have a yellowish or brownish cast. Judging color is a job that can be performed only by experts with proper gem lab equipment. To grade color, the gemologist places the diamond under white light that is constant and free of ultraviolet rays. The stone is placed table down (that is, top down) and viewed through the pavilion. It is more difficult to judge color if the stone is already mounted.The tested diamond is compared to a set of five master stones whose colors have been accurately graded: The color grading scale ranges from D through Z. (A, B and C are not used to avoid confusion with other grading systems that use only those three letters.)
- D - E: The diamonds are colorless.
- F - I: The diamonds are near colorless. Small stones appear colorless when mounted, but large stones appear tinted to the trained eye.
- J - L: Slight traces of color are apparent in mounted stones only to the trained eye.
- M - Z: Mounted stones will display a yellowish tint, even to the untrained eye.
Buying Tips & Suggestions:
- Diamonds are found in almost every color. The Hope diamond is blue. Other diamonds are canary yellow, pink, rose, and green. To avoid confusion, diamonds of intense color are referred to as "fancies". Diamonds of intense color are rare in nature. Those of exceptional quality are very expensive and considered collector's items. The majority of "fancy colored" diamonds are not natural in color but are color enhanced by irradiation or other means. These treatments are done to diamonds of poor color that would have low value in their natural state.
- A difference of one color grade affects price on an average of 10% and sometimes more. For this reason, it is important to purchase jewelry from (or have jewelry appraised by) a reputable jeweler who has gemological and appraisal training, and who has examined the jewelry in a gem lab.
- Intensely colored diamonds may be natural fancies, low-quality stones that have been color-treated, or synthetic diamonds. Natural fancies are far higher in price. If you are buying a colored diamond, be sure the seller explicitly states on the appraisal which kind it is.
- Purchase quality diamonds only from a jeweler who uses a certified set of master color-grading diamonds. Ask whether the seller has such a set. Cubic zirconium (imitation diamond) stones are not acceptable. Reliable gemologists know that only diamond can be used for grading diamond.
- Diamonds that have been irradiated to intense colors can offer some really attractive prices, compared with colorless diamonds or naturally-occurring fancies. The irradiation treatment for color is both safe and permanent.
Carat : The final step in your diamond ring checklist is the carat. This is the size of the diamond. When diamonds are mined, small diamonds are found much more frequently than large ones. This makes large diamonds more valuable. A 2-carat diamond is always more valuable than two 1-carats of the same quality.
Diamonds and other gemstones are measured by carat weight. A carat is 1/5 of a gram, or 200 milligrams. (The word carat comes from the carob bean, which weighs about 1/5 of a gram and was used as a measure in earlier times.) Stones lighter than a carat are measured in points. There are 100 points in a carat. A point is equal to .01 ct.
Caution: Do not confuse this term with karat, the measure used for the fineness of gold.
Buying Tips & Suggestions:
- More carat weight does not necessarily mean more beauty or more value. A diamond that is poorly cut may weigh more than one that is well cut, but it will lack brilliance and may have other problems.
- A low rating for color and clarity will also bring down the gem's value.
- Each of the Four Cs plays an important part in determining a diamond's worth.
- In general, most shoppers prefer a diamond of at least one carat. Consequently, stones that are fractionally smaller than one carat (i.e., .98) can be considerably less expensive. It's worth checking out.
Finally, when choosing a diamond ring, always consider the personal taste and style of the person it is intended for. Do they usually wear a lot of jewelry? Would they prefer a gold or silver setting? Finger size is also important. If a person has small fingers, then the diamond itself will appear larger.
Perhaps the biggest factor to consider when buying a diamond ring is your budget. When buying a diamond ring for an engagement or wedding, popular thought is that it should cost at least one months' salary.For more information on Buying Diamond Ring visit at http://www.halfvalue.com and http://www.halfvalue.co.uk websites.
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