If you're looking to get an engagement ring, an anniversary gift, or a piece of jewelry for whatever reason that has diamonds in it, you need to know some basics before delving into a purchase. There are 5 main pieces of information that you must have about your diamonds, also known as the 5 C's: cut, clarity, color, carat weight and certification (the last of these is by far the most important and we'll find out why later). The most important aspect of a diamond overall is its proportions and not just one subcategory or another.
Cut
Clarity
Color
Carats
A carat is the measurement unit that is used to weigh the diamond but the scale is a little strange. One carat = 200 milligrams or 0.2 grams. Whoever says the size of a diamond doesn't matter is lying. The size does matter tremendously, it is visible to everybody, and the size should also be based on where you want the diamond to be. For example, if you want the diamond to be in a ring and it will be on a small hand, you don't need to purchase one quite as big as for a bigger hand because it will overwhelm the person's features. Carat does not mean the same thing as karat, which is used to describe the purity of gold rather than diamond size. Make sure that the setting you choose is made to fit the carat weight of your diamond before you purchase anything! Also, if you choose to go with a larger diamond and cannot fit it into your budget, consider going with a lower quality of color and clarity.
Certification
Many people believe that certificates are the same as appraisals but this is not true. An appraisal merely places a monetary value on the diamond but does not certify that the diamond is of a certain quality or describe the diamond. A certificate specifies the quality of a diamond and gives a map of the stone's characteristics, pointing out all of the individual flaws and it is proof of the diamond's identity. A certificate does not attach a monetary value to the diamond because these fluctuate highly and are very dependent on the economy and supply. Loose diamonds are valued by the Gemological Institute of America (GIA) or American Gem Society (AGS), although you can get them valued at other labs around the world these are the two highest recognized authorities for diamonds (because of their stringent requirements) in the world. You should always ask for the certification of the diamond and double-check that you should be paying the amount asked and to make sure that you are indeed purchasing a diamond and not a cubic zirconium. Shop around and make sure that you are getting the best bang for your buck, after all these are quite hefty purchases. It is better that you are skeptical in this purchase rather than trusting the sales merchants who are always just looking to make profit and commission.
Shape
The shape is entirely up to you, you should choose whichever is your favorite and you will find most comfortable to wear. Personally, I love the round-cut diamond for its brilliance, light-refraction and practicality as well as beauty.
I highly recommend that you purchase all aspects of your ring separately if you are going to purchase an engagement ring because you are much more likely to get a great deal. If you buy a ring from a department store or a jeweler, you will pay a huge mark-up and you may not be entirely in love with the design. I suggest taking a look at www.bluenile.com for the most accurate wholesale information on settings and diamonds. Go into a jewelry store and find out which size you are, which shapes and settings you like, and then build your own ring on the Blue Nile website and have it shipped home. You would be surprised what a difference it will make in your pocket.