Learn about Diamond Weights

The weight of a diamond is measured in carats. Total carat weight (T.W.) is the total weight of all the stones in a piece of jewelry. For example, a ring with one 1/2 carat stone and two 1/4 carat stones would have a T.W. of 1 carat.

Larger diamonds, or those with more carats, are sometimes considered to be more valuable, but occur less frequently in nature. However, diamonds of the same carat weight may vary widely in value. A diamond with poor color and clarity might be much less valuable than a smaller diamond with a better color and clarity.

Once you've determined what cut, color, and clarity grade you're looking for in a diamond, it's easy to determine the carat weight of diamond that will fit within your budget.

When diamonds are mined, large gems are discovered much less frequently than small ones, which makes large diamonds much more valuable. In fact, diamond prices rise exponentially with carat weight. So, a 2-carat diamond of a given quality is always worth more than two 1-carat diamonds of the same quality. Note that a 2-carat diamond does not appear to be twice the size of a 1-carat diamond when viewed from the top.

To choose the best carat weight of diamond, consider her style, the size of her finger, the size of your setting, and your budget.

■ If you have a set budget, explore all your options and you'll find that there is a wide range of diamond carat weights and qualities available in your price range.

■ If your recipient is very active or not used to wearing jewelry, she may find herself bumping or nicking her new ring. Consider a smaller size diamond or a setting that protects a larger diamond from getting knocked against doors and counters.

■ Also keep in mind that the smaller the finger, the larger the diamond will appear. A 1½-carat diamond solitaire looks much larger on a size 4 finger than a size 8.

■ If you have already chosen a setting, to make sure you choose a diamond to fit, look for the diamond size specifications of your ring in the product catalog or ask your Jewelry By Net diamond and jewelry consultant what size diamond you should look for.

■ Finally, if a large carat weight is important to you, yet you're working within a budget, consider a diamond with a good cut, SI1–SI2 clarity, and an I or J color grade.

Diamond Carat Weight

Diamonds are measured in terms of weight, not size. The heavier the diamond, the greater the carat weight. The name "carat" is derived from the carob seed. These seeds are remarkably consistent in weight and size and so were the favored scale balances in ancient markets. Carat weight should not be confused with "karat," the term used to describe gold’s fineness or purity.

A gem carat equals 200 milligrams, and there are 142 carats to every ounce. A carat is composed of one hundred points. Jewelers evaluate a diamond’s carat weight by using an exceptionally sensitive metric scale that measures weight in points. So, a 1/4 carat diamond is also called a 25 point diamond. Because large diamonds are extremely rare -- and diamonds over one carat in size are becoming increasingly so -- every tiny increase in weight can result in a big increase in market value. Generally speaking, the larger the diamond, the higher the price. Even a large diamond that has so-so color and clarity will cost more than a smaller but finer diamond, simply because the larger ones are scarce.

But the best way to determine what size is best is by getting an idea of what she is expecting. If you plan carefully, you can get some answers without even raising her suspicions. For ideas and suggestions on how to choose the right engagement ring, read our Engagement Ring Guide.

Confidence

Although the standard grading system includes 4 characteristics, at Jewelry By Net we add a fifth C. It stands for confidence. Our diamond buyers select diamonds by using specific guidelines to offer the most popular cuts and qualities at the best possible price. This provides you with the confidence to know that you are receiving the best value.