By: David Cowley
The Gemological Institute of America (GIA), the American Gem Society (AGS), and the International Gemological Institute (IGI) are the three most widely known and respected diamond grading laboratories in the world. Each of the grading laboratories have developed a very similar nomenclature for identifying the 4 C's of diamonds.
Color grading scales used by the internationally recognized laboratories (GIA & IGI for example), ranges from totally colorless (D) to pale yellow or brown color (Z). Brown diamonds darker than K color are usually described using their letter grade, and a descriptive phrase, for example M Faint Brown. Diamonds with more depth of color than Z color fall into the fancy color diamond range.
The coloration of diamonds can be caused by several factors. Impurities trapped in the diamond during its formation, the crystal lattice structure of the diamond, and the exposure to radiation can all lead to the wide verity of colors available in diamonds.
Yellow diamonds are colored because of the impurities that are trapped inside diamonds when they are created. If a few of the millions of carbon atoms have been replaced by nitrogen atoms, then structure of the diamond will not be significantly altered but the clarity will be changed. The amount of color displayed is dependent on the amount of nitrogen involved.
When we see color it is because the object we are looking at reflected a specific wavelength of the light spectrum. A good example of this is a yellow flower. The flower absorbs all of the light except the yellow light, which is reflected by the yellow flower.
In the case of a blue colored diamond some of the nitrogen has been replaced by Boron. Boron will reflect the blue wavelength of the light spectrum. The higher the concentration of boron the more color will be showed. At a level of one or a few boron atoms for every million-carbon atom, an attractive blue color results.
The pink diamonds comes in shades ranging from a pastel rose, such as the Pink Orchid to intense purple-reds of the Moussaieff Red, and the price is determined by the intensity of the color. Pink diamonds have sold for up to $1,000,000 a carat. Unlike the Type I diamonds that derived their color from impurities embedded in the diamond, Pink diamonds are considered a Type II and get their color from a process known as Plastic Deformation.
Type II diamonds have very few if any nitrogen impurities in them. They get their coloration due to structural anomalies caused by Plastic Deformation during the crystal growth. The intense pressure changes the lattice structure of diamonds and has led to the formation of Pink, and Red colored diamonds.
A natural diamond coming into contact with a radioactive source at some point during its lifetime causes some diamonds to develop a green coloration. The time required may be as much as a million years or longer. Green diamonds of this nature are very unique.
The most common form of irradiation diamonds comes from alpha particles found in uranium compounds or from percolating groundwater. Green spots on the surface of the diamonds or a thin green film may develop on the skin of the diamond after long exposure to these particles. Many times this green coloration will be removed during the cutting or faceting process.
Bombardment by beta and gamma rays will color the diamond to a greater depth and in some rare case turn the entire stone green. Heating to temperature to just below 600 degrees Celsius can sometimes also cause a diamond to develop a green ting. Higher temperature may turn the stone to a less desirable yellow or brown color.
Black diamonds are found only in Brazil and the Central African Republic. Approximately 600 tons of conventional diamonds have been mined, traded, polished since 1900. But not a single black diamond has been discovered in the world's mining fields. The geological settings where diamonds are found or mined are virtually identical with the one exception, the Black Diamond.
Black diamonds have been found to contain trace elements of nitrogen and hydrogen. The study published in 2006 analyzed the hydrogen in black diamond samples using infrared-detection instruments and found that the quantity indicated that the mineral formed in a supernova explosion prior to the formation of the Solar System. These diamonds were formed by carbon-rich cosmic dust in an environment near carbon stars. The diamonds were incorporated into solid bodies that subsequently fell to Earth as meteorites.
Article Source: http://www.myarticlemall.com
David Cowley has created numerous articles on Diamonds. He has also created a Web Site dedicated to Diamonds. Visit www.diamonds-team.com
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By: David Cowley
Labels: Why Are Some Diamonds Colored
By Jonathan Blocker [ 05/02/2008 ][ viewed 7 times ]
If you're thinking about purchasing loose diamonds or diamond jewelry, it's a very good idea to make sure that such diamonds are certified diamonds. Such diamonds are accompanied by a document known as a "grading report," which is not the same thing as an appraisal. While an appraisal can give you an idea of the monetary value of your certified diamonds, it is this grading report that is the basis of this valuation.
How Diamonds are Certified
The grading report describes certified diamonds on the basis of four qualities. These are carat, clarity, color and cut, and therefore are sometimes known as the "Four Cs" of certification. The report is for the benefit of those who create and market diamond jewelry, as well as those who purchase it - either as collectors, investors or both.
Those who prepare such reports are known as gemologists. These are technicians who generally have a degree in geology, then go on for specialized training in the study of precious gems and stones; they are to field of geology what cosmetic surgeons are to the field of medicine.
What the Grading
Report ContainsThree of the criteria used to analyze and evaluate diamonds are thoroughly objective, meaning they can be readily measured and quantified. Carat of course is a measure of mass and weight; a carat is equal to 2 decigrams, or roughly 1.5 hundredths of an ounce. Obviously, the more a gem weighs, the greater its value.
With industrial diamonds, the process might stop right there. However, certified diamonds are those used in diamond jewelry, and thus must be pleasing to the eye. The SI Clarity Grade is another criterion by which gemologists evaluate diamonds. The ideal, perfect diamond is rated "FL" for "flawless." The stone is virtually clear, with no cloudy or "cottony" areas or visible cracks. Stones that are clouded and/or cracked are labeled "I3" for "imperfect.
" Color is an important factor when it comes to diamonds. These gems are clear or white to be sure, but can also be pink, amber, blue, green or purple. The saturation of these colors can range from the palest tinge to the deepest, darkest shades as well. Some colors are more desirable than others; rich pink and blue diamonds may command much higher prices than dark amber or even clear ones.
Evaluating the cut is a little more problematic. While it is true that a badly cut diamond may be almost worthless, even among quality cuts, some are more desirable than others. The value of cuts when it comes to certified diamonds is often determined by current market conditions that may change over time.
Objectivity is Vital
It is important to make sure that the grading report that accompanies any certified diamonds have been prepared by a lab that is unaffiliated with the company or individual who is selling them, for reasons that should be obvious.
About the author:Jonathon Blocker specializes in custom diamond jewelry, loose diamonds, and colored diamond engagement rings. He is a consultant for GemFind.com, a trusted name in the jewelry industry since 1999. Article Source: http://www.free-articles-zone.com/author/8595
Labels: How Diamonds are Certifies
By Jonathan Blocker [ 14/02/2008 ][ viewed 4 times ]
The art and science of diamond cutting dates back to the mid 1500s, and princess cut diamonds represent the latest and one of the trendiest available. Part of the appeal of princess cut diamonds is the rectangular shape that manages to retain the sparkle and fire of more traditional round cuts.Diamond Cuts GaloreDiamond as jewelry dates back to ancient Rome, but it wasn't until the High Renaissance that the first diamond cutters' guild was formed in the Belgian city of Antwerp. Natural diamonds are octahedral in shape (visualize two pyramids with their bases glued together). The earliest method of cutting loose diamonds was known as the point cut, which simply followed the gem's natural shape. During the early Renaissance, it was learned how to cut off one point of the octahedron; this was known as the table cut. The problem with these early cuts is that they failed to reveal diamonds' light dispersion, which is what jewelers and gemologists call the stone's "fire." Diamonds in the early days were prized mainly for hardness and surface luster, but had little in the way of shine and sparkle.Revealing the 'Inner Light'The first brilliant cut diamonds date from the mid-1600s. Although fairly dull by modern standards, these early "Mazarin" diamonds were substantially more brilliant than those cut even a century earlier.Modern brilliant diamonds were first produced around 1900; for decades, round cuts were the most common as well as the most popular, as these maximized the gem's fire and brilliance.Comeback of the Square CutPrincess cut diamonds are gaining in popularity, currently ranking #2 among those who collect loose diamonds and diamond jewelry. Among diamond cutters, princess cut diamonds are the more desirable, as this particular cut wastes very little of the rough diamond; thus, the diamond retains more of its original carat weight. This also makes princess cut diamonds less expensive than their traditionally round cut counterparts.Princess cut diamonds made their initial appearance in 1979, and combine the brilliance provided by a traditional round cut with the square or rectangular shape. It was an innovation of one Israel Itzkowitz, who worked at the Ambar Diamond Company in Los Angeles, California. His work was based on three years of study that resulted in a cut that was literally the "best of both worlds" - square and rounded.Because of the tetrahedral molecular structure of diamonds, the princess is really one of the most efficient ways to cut diamond. Princess cut diamonds are also known as "modified square brilliant."
About the author:Jonathon Blocker specializes in diamond jewelry and princess cut diamond engagement rings. He is a consultant for GemFind.com, a trusted name in the jewelry industry since 1999. Article Source: http://www.free-articles-zone.com/author/8595
Labels: The Benefits Of Cut Diamonds
Rings can be a very personal thing. The ones you wear can say a lot about your personality and who you are. So if you are going to pick out one for yourself, where do you start? There are such a multitude of rings to choose from today. There are modern styles, classic styles, and antique styles, just to name a few.
Some are plain gold or platinum with no gem stones, some have rubies, sapphires, or emeralds. Those are just some of the ones you can pick from in a jewelry store. What if you decide you want to have a ring made by a custom designer? The choices suddenly become endless.
The one choice for a ring that can never be wrong is a diamond. Who does not love a diamond? They are usually clear white and stunning. Depending on the setting you choose, they can be worn almost anytime, anywhere, and with almost anything. With color gemstones, it can be a problem matching them to all outfits and can limit when you wear it. Generally you will not have that concern with diamond jewelry.
When picking out a ring, start with the metal it will be set in. If the bulk of your other jewelry is gold tone, then a 10k or 14k yellow gold might be the best choice. If you own more silver toned pieces, you might rather have it be 10k or 14k white gold, or even platinum.
If you go with gold, white or yellow, consider how regularly you will wear your diamond ring. If it will be daily, or if you are rough on your jewelry, 10k will most likely work best because it is not as soft as 14k gold. It will wear out less quickly on the shank, or band part of the ring. This is a common problem when wearing a ring continuously, because constant wearing will weaken the back side of the shank and sometimes will lead to it breaking.
When picking the setting for your diamond, keep the style in mind. Think about what type of clothing you wear most. Do you dress casual a lot, or do you dress up more often or even daily?
Your setting should be something that matches what you wear most. This will limit your beautiful new ring sitting at home alone in your jewelry box because it does not look well with your attire, Women have always tended to worry more about small details like this, but men have begun to be just as picky over the last couple of decades.Article source: ContentLog.com
You are currently reading the entry “The Diamond Ring Comes In Many Shapes And Sizes” written by klar dror on October 30th, 2007 at 6:52 pm in Beauty.