To get the best diamond possible, and the best value for your money, you need to learn what factors affect a diamond's beauty and value. This web page describes these factors, along with recommendations on minimum standards, information on treated diamonds, purchase tips, getting an appraisal, and insurance. Unlike other web pages about diamonds that are run by someone trying to sell you something, I am not trying to sell you anything! I have no ulterior motives and no commercial biases. I simply want to share with you the results of my diamond buying research, and help you to become the smartest and savviest diamond buyer possible. I promise you that if you read this page and those pages directly linked to it, you will know much more about diamonds and buying them than a great majority of the general public, and possibly many jewelry store employees.
For information about this web site and its author, refer to the Home page.
A diamond's beauty and value are determined by four factors. Listed in order of importance, they are the Cut, Color, Clarity, and Carat size of the diamond (the 4 C's). Note that the Cut of a diamond refers to how well proportioned and finished it is, as opposed to its shape, such as round, pear, heart, etc.
Each of these factors, with the exception of carot size, is graded based on scales developed by the Gemological Institute of America (GIA). The GIA is recognized worldwide as the highest authority on diamond grading. The GIA, through its Gem Trade Laboratory division, issues a Diamond Grading Report on diamonds submitted to it. This report is the most respected documentation that may accompany a diamond. The How to Read and Understand a Diamond Certificate web page provides good tips on interpreting this report.
Obviously, you want to get the largest and best diamond possible for your price range. The 4 C's all contribute to the value of a diamond, however a diamond with the top grade in each category is probably out of your price range. Therefore, you have to compromise on which factors are important to you. There are certain minimum grades in each category that you should insist on. One diamond expert, Fred Cuellar, recommends minimum grades of SI-1 Clarity, I Color, and Class II Cut.
SI-1 is the lowest grade where imperfections are not visible to the naked eye. It doesn't make any sense to pay for higher levels of clarity than SI-1, since you can't see the difference without magnification.
The lowest grade of color that looks "white" is the I Color. When weighing the importance of color, you should focus on the "near colorless" color grades of G, H, and I. The "colorless" color grades of D, E, and F may price a diamond out of your budget.
The Cut of the diamond (also known as "make") is the most important of the 4 C's and directly affects the diamond's brilliance and fire (light reflection and refraction) as well as it's sparkle. Since no one wants a dull, lifeless diamond, you must consider the quality of the cut. The GIA grades cut from Class I (best) to Class IV(worst). Unfortunately, the GIA does not put the cut grade on the grading report it issues. This means that while the Color, Clarity, and Carot size are easily quantified, the Cut is not. You can generally ascertain the cut quality by looking at the Proportions section of the grading report. The two most often quoted proportions from this report are Depth % and the Table %. The rule of thumb for round diamonds is that these two proportions should each be 60% (the 60/60 rule). However, you may have read that an "Ideal Cut" diamond should have a 53% table. While this is technically true, see this web page as to why you should follow the 60/60 rule. Since you will encounter diamonds that vary from this rule, refer to the "very good grade" column of this chart for recommended ranges of these proportions. The girdle of the diamond should not be extremely thin or thick, and well cut diamonds have faceted girdles. The culet size should be none to medium. By the way, "culet" is NOT pronounced, nor spelled "cut-let"! The diamond's Finish directly affects its brilliance and sparkle. The finish is broken down into two parts: Polish and Symmetry. Both of these should be rated at least "good" - well cut diamonds will be graded "very good" or "excellent".
This describes a diamond's reaction to ultraviolet light, such as is found in sunlight, or from black lights (used on the dance floor of nightclubs) - it causes the diamond to glow; usually blue, but other colors are possible. The rule of thumb is that for diamonds graded H color or lower, blue fluorescence can be positive, making the diamond appear whiter. Conversely, for diamonds graded G color or higher, it is a negative factor, making them appear milky and detracting from their appearance. Avoid strong fluorescence and any color other than blue. Fluorescence in diamonds is a controversial subject, and there are many opinions about it. The GIA recently did a study that found that blue fluorescence generally either helps or has no effect on a stone's appearance. On the other hand, some diamond experts, such as Fred Cuellar, dislike fluorescence.
On the GIA grading report, it's best to have no entries in the comments section. If crown angles are noted, then the stone is poorly cut and should be avoided.
There are several methods by which a diamond with a poor clarity grade may be doctored to artificially improve its clarity. A diamond may be fracture-filled (euphemistically called "clarity enhanced"), a process where a diamond's cracks are filled with a glass like substance. This substance can degrade and discolor because of light, heat, or cleaning chemicals. Since this treatment introduces foreign substances and is not permanent, the GIA will not provide diamond grading reports on fracture-filled diamonds. Another treatment is to laser drill a diamond. This is used to burn out black carbon inclusions in the stone. The laser burns a hair-thin tunnel to the inclusion, which is burned out by the laser itself, or with the help of acid that is forced into the tunnel. Laser drilling can introduce structural weaknesses in the diamond, which may cause it to become damaged when a jeweler works on the ring holding it - unless the jeweler knows about the drilling and takes precautions. The GIA will note laser drilling on its grading reports. You should not buy treated diamonds.
1) Only buy a diamond with a GIA Diamond
Grading Report! This should be your primary rule. Abiding by this rule
guarantees you the following:
a) an unbiased, accurate, and universally accepted grading of the 4 C's
b) ability to comparison shop reliably, since all GIA graded stones
have had exactly the same standards applied to them
c) assurance that the
diamond is natural and not treated (verify that laser drilling isn't mentioned on the GIA
report)
d) information on the report uniquely identifies a diamond, allowing
its authenticity to be verified
in the future
e) an indisputable, accurate description for insurance purposes (along
with an appraisal)
Make sure the report is less than 6 months old.
2) Buy the diamond loose, not mounted
in a ring. The reasons for doing this include:
a) problems with the diamond may be hidden by the ring setting
b) allows you to accurately examine for yourself the 4 C's of a
diamond, and decide the relative merits of each
c) gives you the option of buying the diamond first, and then shopping
for the ring with your loved one (even at a different store)
3) Ask the jeweler to weigh and measure the diamond in front of you, and point out its clarity related features under magnification. Have them show you the diamond's fluorescence (if any). Then compare this to the GIA report. This will give you confidence that the diamond being shown to you matches its GIA report
4) Select a quality jeweler - find out about their reputation, credentials, policies, and equipment. Do not buy your diamond in a department store!
5) Comparison shop several stores:
a) will guide you in determining the market price in your area for what
you want.
b) the Cut of the diamonds carried by stores will vary - seek out the
best cut you can find; remember the 60/60 rule and look for a finish graded better than
"good".
c) ask jewelers for copies of the GIA grading reports of the stones you
are interested in (for later comparison)
d) do not let yourself be pressured into buying a diamond during the
same visit when you first see it - beware of high pressure sales tactics; like an offer
that will evaporate if you leave the store without accepting it
e) only consider leaving a deposit on a stone you are seriously
interested in, and always use a credit card to do so
6) Ask prospective jewelers to see the current Rapaport Diamond Report, which comes out weekly. This is a wholesale price list widely used by the industry. Compare the prices you are being offered against the Rapaport report prices.
7) Consider buying your diamond wholesale in New York City's Diamond District (in Manhattan on 47th St. between 5th and 6th Ave.). This is the wholesale market for diamonds in the United States, and the primary source for jewelers. Wholesalers and jewelers here will have no problem showing you the current Rapaport report, and will typically sell you diamonds at up to an 18% discount from Rapaport! You may want to call some of the jewelers listed in the Jeweler's Directory and compare their prices to those you have gotten in your area.
8) Read the tips, warnings, and suggestions from these web pages:
a) Buying
a Diamond Tip Sheet from the Attorney General of the State of Idaho
b) Tricks of the
Trade from Fred Cuellar's web site
c) Buying jewelry -
pitfalls and how to avoid them
9) For a ring holding a round diamond, I suggest that you get a platinum ring, Tiffany style, with six prongs. Platinum is stronger than gold and will not distract from the diamond's color, plus it is hypoallergenic and resists tarnish. The Tiffany style setting lifts the stone up into the light to maximize its brilliance. Six prongs look more symmetrical for a round diamond than four, plus it holds the diamond more securely.
As soon as possible after you purchase your diamond jewelry, get it appraised. This will verify that your diamond matches the GIA report (show it to the appraiser) and confirm the value of your purchase. Just as important, you should insure your diamond jewelry, so tell the appraiser it will be for insurance purposes. Homeowners or renters insurance will not provide sufficient coverage unless you schedule the jewelry - check with your insurance agent. Separate jewelry insurance is available from Jeweler's Mutual Ins. Co. You want the appraisal to reflect the fair market value to replace the ring - underinsuring it will leave you financially exposed, and overinsuring it will lead to higher than necessary insurance premiums. What should you look for when hiring an appraiser? Because of a conflict of interest, do not get it appraised at the same place you purchased it from. The appraiser should be independent and not involved in buying or selling jewelry. Do not use an appraiser who's fee is based on the appraised value - this is an obvious conflict of interest. The appraiser should be a Graduate Gemmologist (GIA) and a member of an appraisal association. In New York City, I would recommend the appraisal service of the International Gemmological Institute (IGI)
Two books I have bought and recommend are:
a) Diamond
Ring Buying Guide - has great close up pictures of diamonds illustrating the topics
covered
b) How to Buy
a Diamond : Insider Secrets for Getting Your Money's Worth - by diamond expert Fred
Cuellar
I have no professional training in any matters relating to diamonds or jewelry. I can make no warranties that any information presented here is accurate. All information presented here is on an "as is" basis and should be used at your own risk. All opinions stated on web pages linked to from this page are the responsibility of their authors. You should consult with a GIA qualified professional jeweler before making any jewelry purchase.
For information about this web site and its author, refer to the Home page
Last updated :07/22/2006
