Should you buy a certificated diamond?
Nothing will ruin an engagement faster then finding out from an appraiser that your diamond is not what it was represented to be. Some retailers count on the fact that only a minority of customers actually take their purchase and have it appraised. If you are thinking about buying a diamond that doesn't have a certificate just remember there is no guarantee of quality. You are putting way too much trust into a salesperson's opinion. They are always working on commission and will have a hard time not giving their diamond the best potential grading. The problem is that you want to compare apples to apples. If somewhere you see a 1 carat G color, Si1 diamond for $5,000 and in another store for $4,000 you will assume that you just got a better deal. But if the second stone is 'slightly' misgraded, the first one is actually the better price.
There are 3-4 labs that do most of the certification for local diamonds. In order of their accuracy, they are:
1) Gemological Institute of America or GIA
2) American Gemological Society or AGS
3) International Gemological Institute or IGI
4) European Gemological Labratory or EGL
The last two have a much more lenient standard, favoring the industry and the retailer. I would suggest that it is in your best interest to only deal with GIA certified diamonds. Don't ask if the diamond is certified - they should give you that information unsolicited. If you like a stone get a xerox copy of the certificate so you can compare it to another stone in another store. Never have grading scribbled on a business card. Too much important information will be left out.
If you have any further questions feel free to contact me at Stefan@elsarings.com