Top 20 Diamond Scams

The 20 most common scams in stores
and 13 precautions to avoid them.



Why Certificates from GIA or AGS?

In Your Best Interest ::

If you want the best diamond price and if you want to receive what you are promised …always, always insist on a diamond grading report (usually but not accurately called a “Cert / Certificate“) from GIAAGS, or at least from EGL. (GIA and AGS are the world’s most respected gemological laboratories). Other certificates do not carry as much weight because they are either less respected or less known.

Certificates Are Crucial

You MUST get a diamond grading report (usually, but inaccurately, called a Cert / Certificate) from the most respected independent labs (GIA-GTL or AGS-AGSL or at least EGL-USA), because ::

  • Jewelers Overstate GradesThe main reason you want a certificate ::
    Every “uncertified” diamond is definitely overgraded by a grade or two in both color and clarity (because the FTC actually allows this much error and stores take advantage of it) making every store-graded diamond sound much better than it is.Please insist that you receive a diamond grading report from a respected laboratory (stay with GIA-GTL, AGS-AGSL, or at least EGL-USA) that has no financial interest in the diamond you are buying. For instance, a diamond quoted as F color / VS-2 clarity by a store, will actually be graded at GIA or AGS at least down to a G / SI-1 and quite likely to an H / SI-2, if you sent it to one of the best independent labs for more conservative grading.
  • The Only Way to Know the True QualityThe value of a good lab certificate when buying a diamond is undeniable. If you do not receive a diamond grading certificate from an unbiased, independent, respected laboratory (basically GIA and AGS) you are not getting the diamond you are being promised.
  • The Only Unbiased GradingSmall, local labs are often connected in some way with a store, so they tend to grade diamonds more favorably in order to help make the sale. The GIA (GTL) and AGS (AGSL) labs are very conservative in their grading because they do not sell diamonds and do not receive any portion of diamond sales. A certificate from one of these labs is the best way to get the diamond you want and avoid paying an F color price for a G color quality, for instance.
  • The Best Security During RepairsPeople sometimes ask: “How can I be sure I will get the same diamond back when I have it cleaned or repaired at a jewelry store?” Though it is actually very rare that any jeweler would switch stones intentionally, accidents can sometimes happen in a busy store. The key is to have a certificate that maps your diamond’s unique inclusions like a fingerprint that you can check in the store before you accept it back. Many of the labs also permanently laser inscribe the certificate number right on the girdle of the stone, where you can easily see it with a 10x jewelers’ loupe. In either case, the rare jeweler that would intentionally switch a stone will just wait for an easier customer to swindle. A lab certificate gives you the best protection against these problems.
  • The Greatest AppreciationA certificate enhances the appreciation of one of the most treasured gifts in the world. It adds dignity and confidence in your partner’s eyes when she sees that you cared enough to buy the very best and have the papers to prove it.
  • Too Difficult to Learn It AllIt would be very difficult and time-consuming for a layperson to learn enough to properly assess all the complex factors of diamond quality and pricing. You would have to become a diamond grader. It is not practical to take six months of in-residence training to become a gemologist for an item you only buy once in a lifetime. A detailed certificate saves you enormous amounts of time by supplying an expert evaluation.
  • Protect Your InvestmentAlthough we rarely recommend diamonds as a true investment like stocks and bonds, a certificate makes it so much easier to sell a diamond when you want to trade up or sell it later. Without one, many dealers will hesitate to buy such an unknown quantity. You will have to get a certificate later if you ever do sell or trade up, so you might as well get one now and enjoy all the other benefits in the meantime.

Sample Certificates

For detailed explanations of the various certificates, go to the web site for each laboratory to see a sample certificate ::

GIA-GTL (Gemological Institute of America – Gem Trade Laboratory) ::

AGSL (American Gemological Society Laboratories) has many services for grading diamonds ::

If these links get out of date and the sites change their URLs please let me know!