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BUYER'S GUIDE FOR DIAMONDS

    Grading Laboratories

  • There are many different diamond grading laboratories that all have their own diamond grading report. It is important to look for a grading report from a highly respected diamond grading laboratory. Some of the most well known laboratories are GIA, EGL, IGI and AGS. While a grading report from any of these laboratories will increase the value of your diamonds significantly, for many in the diamond industry GIA is the leading diamond grading laboratory.

  • GIA - Gemological Institute of America. Founded in 1931 in Los Angeles, the GIA created and introduced the international grading system. Headquarters are still located in Los Angeles. GIA is the foremost authority on diamonds. They set the standard for accuracy in grading diamonds especially based on color and clarity. Labs from all over the world usually carry GIA master set stones to compare colors and clarity grades when they're uncertain how to grade a stone. All truly "important" diamonds are sent to this lab above all others.
  • IGI - International Gemological Institute. The oldest institute of its kind in Antwerp. Set up in 1975 with labs in New York, Bangkok, Mumbai and Tokyo. I.G.I. provides a detailed certification that is not as strict as G.I.A. Like the E.G.L. the I.G.I. certification also provides more information than the G.I.A. diamond report by including the important pavilion and crown angles in their diamond report. Diamond grades rarely vary over one grade from G.I.A. Like E.G.L., I.G.I.'s diamond report cost less and is used mostly by diamond cutters for smaller diamonds although larger diamonds are also available. You must be aware that diamonds graded by E.G.L and I.G.I. can be less in price than diamonds graded equal by G.I.A. and may sometimes not match G.I.A. if resubmitted.

  • EGL - European Gemological Laboratory. EGL was originally opened in Antwerp in 1974, and now has laboratories in Antwerp, New York Los Angeles, Johannesburg, Paris, London, Israel and Seoul. This lab is a major player in the US with more labs than any other. Their passion for their work and commitment to the diamond industry to provide fast, accurate and dependable grading has given them a prominent place in this market.

  • AGS - American Gem Society Founded in 1934 by Robert M. Shipley who also founded the GIA. The AGS is based in Nevada, USA. Currently this lab sets the standard for precise measurements of cut parameters. No other major lab in the world goes through such detailed analytics to properly determine if a diamond is cut to ideal proportions or not like the AGS does.

    Diamond Shapes

  • Diamonds are natural crystals of varying size and shape formed in the earth over millions of years. The traditional round brilliant diamond, though the most popular diamond shape of all, is hardly the only one.

  • Round Brilliant Diamonds
    This shape has set the standard for all other diamond shapes, and accounts for more than 75% of diamonds sold today. 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 Diamonds
    An even, perfectly symmetrical design popular among women with small hands or short fingers. Its elongated shape gives a flattering illusion of length to the hand.
    Marquise Diamonds
    An elongated shape with pointed ends inspired by the fetching smile of the Marquise de Pompadour and commissioned by the Sun King, France's Louis XIV, who wanted a diamond to match it. It is gorgeous when used as a solitaire or when enhanced by smaller diamonds.
    Pear Diamonds
    A hybrid cut, combining the best of the oval and the marquise, it is shaped most like a sparkling teardrop. It also belongs to that category of diamond whose design most complements a hand with small or average-length fingers. It is particularly beautiful for pendants or earrings.
    Heart Shape Diamonds
    This shape has set the standard for all other diamond shapes, and accounts for more than 75% of diamonds sold today. 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.
    Emerald Cut Diamonds
    This is a rectangular shape with cut corners. It is known as a step cut because its concentric broad, flat planes resemble stair steps. Since inclusions and inferior color are more pronounced in this particular cut, take pains to select a stone of superior clarity and color.
    Princess Cut Diamonds
    This is a square or rectangular cut with numerous sparkling facets. It is a relatively new cut and often finds its way into solitaire engagement rings. Flattering to a hand with long fingers, it is often embellished with triangular stones at its sides. Because of its design, 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 not uncommon.
    Trilliant Diamonds
    This shape has set the standard for all other diamond shapes, and accounts for more than 75% of diamonds sold today. 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.
    Radiant Cut Diamonds
    This square or rectangular cut combines the elegance of the emerald shape diamond with the brilliance of the round, and its 70 facets maximize the effect of its color refraction. Because of its design, 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 not uncommon.
    Cushion Cut Diamonds
    This shape has set the standard for all other diamond shapes, and accounts for more than 75% of diamonds sold today. 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.


    Loose Diamonds and Certificate FAQ's

  • What is a Diamond Grading Report or Certificate?
  • A certificate is a diamond grading report issued by an independent laboratory detailing the diamond's weight, dimensions, color, clarity and cut. The GIA (Gemological Institute of America) and EGL (European Gemological Laboratory), whose standards are the strictest in the diamond industry, are the undisputed international authorities on diamond grading and gem identification. The GIA issues a Diamond Grading Report or Diamond Dossier. The EGL calls their report a Diamond Certificate.

  • Why is certification important?
  • A certification is an assurance of quality. A diamond certification is a detailed quality report issued by an accredited independent gemological laboratory. The most recognized gemological laboratories that provide certified diamond quality reports to the diamond and jewelry industry are listed below.

  • G.I.A. - Gemological Institute of America
  • E.G.L. - European Gemological Laboratory
  • A.G.S. - American Gem Society
  • I.G.I. - International Gemological Institute.

  • Why don't all diamonds come with a certificate?
  • For the most part, diamonds of higher quality and larger sizes are certified. You will also find smaller high quality diamonds of high quality that have been certified. Where you won’t find certificates are the lower or promotional grades. At this level there is no return on the investment of the certification. Frequently, the higher grades are certified to insure the highest price will be paid from dealer to dealer.

  • Is a certificate the same thing as an appraisal?
  • No. A diamond appraisal is the opinion of an individual appraiser as to the quality of a diamond and his/her opinion as to the monetary cost of replacing the stone. An appraisal is useful only as a tool for the insurance industry when a customer needs something replaced due to loss or theft. Appraisals are typically far above the actual retail cost of a diamond. In contrast, a certificate is issued by an independent laboratory that has had one or more staff members evaluate the stone for its specific quality. A certificate contains no price estimates; it is simply the assessment of the lab as to the exact quality of the diamond you are selling.

  • Do you provide gemological certificates for your products?
  • Yes we do provide gemological certificates for most of our products. The loose diamonds come with GIA, IGI, EGL, or AGS certificates.

  • What is the importance of a certificate?
  • A certificate assures all customers of a diamond's value and quality. The report gives a detailed enlisting of the key characteristics of each diamond which includes the 4C's and makes it almost impossible to falsify. The certificate marks the credibility of the stone under consideration.

  • Do you provide gemological certificates for your products?
  • Yes we do provide gemological certificates for most of our products. The loose diamonds come with GIA, IGI, EGL, or AGS certificates.

  • Why does Gem Stone King prefer a diamond with a certificate?
  • The gemological laboratories are essentially non-profit organizations, so the certificates they issue are not biased. Also, diamonds sent to the gemological laboratories for certification are examined by many different expert graders in the determination of exact quality. A certificate allows us, at Gem Stone King to provide our clients with a certified, secured, and reliable shopping experience.

  • How do I know that the item I purchase is the one that I will receive?
  • Your purchase will arrive with an original certificate for loose diamonds. Each product is checked and compared to its certificate by one of Gem Stone King’s experts prior the shipment to ensure a match between the item and the certificate. You can either have your purchase appraised by a local jeweler or inspected for your piece of mind. If you are not satisfied with the appraisal of your purchase order you can return the item.

  • At Gem Stone King, we understand how important the purchase of your diamond jewelry is. In order to assure you that you’re receiving the value and product you expect, we provide a grading report from a well-known and well-respected independent gemological laboratory. A complete listing of the stones quality and all attributes of the item are listed for you to see, before you buy.

  • A grading report may also include a diagram that “maps” the diamond's inclusions. Since each diamond is unique, the diagram acts like a fingerprint to identify that particular diamond. A diamond can be compared to its certificate to help you retrieve it if ever stolen.

  • It is important to note that a diamond grading report from most independent laboratories is NOT an appraisal, which estimates the monetary value of a particular item. It is simply an impartial, informed opinion made by an experienced gemologist as to the grade of the stone.

  • What do I look for in the quality of a diamond?
  • While making a diamond purchase, you need to keep in mind the 4C's- cut, color, clarity and carat- which are the key characteristics in a diamond. Generally the best quality diamonds are those with maximum brilliance which is determined by the cut of the diamond and no tinge of yellow in case of the regular colorless diamonds. The carat, that is the weight of the diamond, is most often a matter of personal tastes.

  • Which of the 4C's is the most important?
  • The first 4C's (carat, cut, color, clarity) are what determine the value and cost of a diamond. The thing to keep in mind is that everyone has a budget when buying a diamond. Quality must always be leveraged against quantity to keep your budget in line. It is not always easy to find a balance, but by understanding and paying attention to the things that establish price it will make it easier.

  • How can I be sure of the quality of your products?
  • Our aim is to achieve absolute customer satisfaction by providing the highest quality. With our on-staff gemologist and quality assurance department, you can rest assured that you are getting only the highest quality, best product.

  • What is a Carat? What is the difference between Carat and Karat?
  • A carat is 100 points in diamond weight. A carat is also 1/5th of a gram. It is also 1/14200th parts of an ounce. This is a very small unit of weight effecting price in a very big way. Karat, is the measure of gold purity. It has nothing to do with stone weight.

  • Carat Fractions and Their Decimal Equivalents:
  • This scale is recognized worldwide, but could vary plus or minus one point outside the USA.


  • Carat

  • Carat, abbreviated "ct." is a measure of weight used for diamonds. One carat is equal to 1/5 of a gram (200 milligrams). Stones are measured to the nearest hundredth of a carat. A hundredth of a carat is also called a point. Thus a .10 carat stone can be called either 10 points, or 1/10 of a carat. Small stones like .05, and .10ct are most often referred to by point designations.

  • The carat, as a unit of weight, is derived from the carob seed which was used by early gem traders to weigh diamonds. Since a carat is a unit of measure and not size, two diamonds of the same carat weight may appear to be different sizes depending on how the diamond is cut.



  • Clarity

  • The Clarity Grading Scale developed by the Gemological Institute of America (GIA), outlined below is the most widely accepted grading system in the world.

  • The carat, as a unit of weight, is derived from the carob seed which was used by early gem traders to weigh diamonds. Since a carat is a unit of measure and not size, two diamonds of the same carat weight may appear to be different sizes depending on how the diamond is cut.

  • Grade Description
    F Flawless. The diamond shows no inclusions or blemishes of any sort under 10X magnification when observed by an experienced grader.
    IF Internally Flawless. The diamond has no inclusions when examined by an experienced grader using 10X magnification, but will have some minor blemishes.
    VVS1, VVS2 Very, Very slightly included. The diamond contains very small inclusions that are difficult even for experienced graders to see under 10X magnification.
    VS1, VS2 Very slightly included. The diamond contains small inclusions such as small crystals, clouds or feathers when observed with effort under 10X magnification.
    SI1, SI2 Slightly included. The diamond contains inclusions (clouds, included crystals, knots cavities and feathers) that are noticeable under 10x magnification.
    SI3 Slightly included. The diamond contains inclusions(possible large feathers or large crystrals) That are obsious under 10x magnification but not to the visible eye.
    I1, I2, I3 Included. The diamond contains inclusions(possible large feathers or large crystrals) That are obsious under 10x magnification and visible to the naked eye.
  • Now you will ask "Which clarity grade should I choose"?
  • Fl and IF are very rare diamonds and very expensive for the average person's pocket.
  • VVS and VS are very good clarity diamonds but are still quite expensive.
  • More affordable and very good choices are SI1, SI2, and I1 called also "eye-clean" because they have no inclusions visible to the naked eye.

  • Every diamond is unique and possesses its own individual natural characteristics referred to as inclusions and described as "nature's fingerprints". These inclusions, such as minerals or fractures, appear while diamonds are formed in the earth. They may look like tiny crystals, clouds or feathers. The number, size, color, nature and position of the inclusions determine the clarity of the diamond.

  • Color

  • Color refers to the presence or absence of color in white diamonds. Acting as a prism, a diamond can divide light into a spectrum of colors and reflect this light as colorful flashes called fire. Just as when looking through colored glass, color in a diamond will act as a filter, and will diminish the spectrum of color emitted. The less color in a diamond, the more colorful the fire and the better the color grade. Diamonds are assigned color grades by comparing them to diamonds with color grades which have been certified by the GIA as master color comparison diamonds. The GIA grades color alphabetically from D (totally colorless) to Z (yellow). See chart below:
  • Color differences are very subtle and it is very difficult to see the difference between say, an E and an F. Therefore, colors are graded under controlled lighting conditions and are compared to a master set for accuracy. When determining the color of a diamond, it is crucial to see the diamond unmounted.


  • Champagne Diamonds - Color Scale

  • Champagne Diamonds are naturally colored diamonds that are produced in a wide range of colors from light straw to rich cognac. They have not been treated in any way - the color is completely Natural!
  • Many diamond lovers maintain that they are much more lively and sparkling than the top whites. We will let you decide for yourselves as you browse through our collection...
  • Please use the color on the picture as a reference only. The picture simply cannot do them justice as to the beauty of these gems.

  • What is HPHT Treatment?
  • HPHT stands for "high-pressure high-temperature." It is a diamond treatment that permanently changes the color of diamonds, removing brownish colorations.
  • How is it done?
  • The HPHT treatment involves placing a diamond in a pressure vessel and squeezing the stone at high pressure and high temperature for a few minutes or less (at pressures close to those used to grow diamonds, and temperatures of about 2,000 degrees Celsius).

  • High Pressure High Temperature Treatment (HPHT)
  • HPHT was first used to turn yellowish diamonds into fancy colored gemstones, but now it's also used to transform some brown diamonds into colorless diamonds that can be sold for a much higher price. Some companies claim HPHT isn't a treatment at all, calling it a technique that finishes the job nature started.
  • HPHT is permanent. The Federal Trade Commission (FTC) requires that HPHT be disclosed.

  • How is it done?
  • The HPHT treatment involves placing a diamond in a pressure vessel and squeezing the stone at high pressure and high temperature for a few minutes or less (at pressures close to those used to grow diamonds, and temperatures of about 2,000 degrees Celsius).

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