As with all precious gems, the weight, and therefore the size of a diamond, is expressed in carats. The carat originated as a natural unit of weight: the seeds of the carob tree. Diamonds were traditionally weighed against these seeds, however, the system was later standardized and one carat was fixed at 200 milligrams (1/5 of a gram).
One carat is divided into 100 “points” so that a diamond of 25 points is described as a quarter of a carat. Size is the most obvious factor in determining the value of a diamond, but two diamonds of equal size can vary significantly in value, depending on the other characteristics of cut, color and clarity.
Tips to help you determine the right carat weight
Some considerations you will have to keep in mind: the size of the recipient’s finger, personal preferences, the type of setting and the most important factor, the budget. Try looking at the purchase in the following order.
First, decide on to your budget and then explore the various qualities and designs available in that price range.
Factor in the shape of the finger. If the fingers are long, a small carat diamond may look even smaller and vice versa.
Be sure to match the setting of the diamond ring with the carat size. For example, a wide band can make a stone look smaller than it might with a narrower band.