All precious commodities have a system for giving the weight of the items, and this is no different for precious gems such as diamonds. While the cut of a diamond arguably has the greatest impact on the overall desirability of a diamond, the carat has the heaviest impact on its pricing. This is due to the fact that carat refers to the actual weight of the diamond and it is a diamond's weight that is one of the primary indicators for how rare a diamond is. Simply stated, the heavier a diamond is, the more rare it will be and thus the more expense.

It is important to be aware that while the term carat refers to a diamond's weight, it does not refer to its dimensions or shape. The carat weight of a diamond can have an effect on its dimensions and shape, but neither the dimensions nor the shape is wholly dependent on the carat weight. For example, you could find yourself looking at two diamonds that look equal in size as you look down upon them. This does not mean that they have the same carat weight, however. A diamond can be cut to look larger than it is, through increasing its diameter and decreasing its depth, or through other cut techniques. The term carat is used to reference the diamond's actual weight, nothing more and nothing less.

Be also aware that while a diamond is priced in great part based on its carat weight, it is not simply priced on the whole diamond weight. Diamonds are priced on a per-carat pricing system. This means that if a diamond is 3 carats, the cost of the diamond is based on the cost of each carat in the diamond added together, also known as the total carat weight. The cost per-carat is not stationary as you go up in carat size either. For example, if a one-carat diamond were priced at $7500 a carat, its total carat price would be $7500. One might think that a comparable diamond of two carats, with all other factors being equal, would also be $7500 per carat, with the total carat price being $15000. This is not the case. A diamond's per-carat price goes up exponentially based on the carat cost points on the diamond pricing report.

The exponential rise of the per-carat price in the diamond is a result of the fact that the rough for the heavier diamonds is rarer than the rough for smaller diamonds. Due to this, the heavier a diamond is, the exponentially greater the per-carat price will be. The aforementioned one-carat diamond might be priced at $7500 per-carat, whereas the comparable two-carat diamond could be $10000 a carat, or $20000 for the whole diamond. Meanwhile, a three-carat diamond of comparable characteristics could have a $15000 per carat price or a total carat weight price of $45000 for the entire diamond. It is for this reason that oftentimes if you are looking for a large total carat weight for the diamond piece, such as a diamond engagement ring, the best choice might be to have a multiple stone setting, as each stone has its own per-carat price.

It is the rarity of large diamond rough that is one of the primary reasons not all diamonds are ideal cut, as diamond cutters use the maintenance of carat weight as their primary motivation when cutting a diamond, and the ideal cut round is extremely wasteful. It is also useful to note that due to the effect of traveled light distance on diamonds, larger diamonds can often appear to be more brilliant than smaller stones. This is due to the greater prismatic effect resulting from the additional distance the light has to travel within the diamond.

While it is important to be aware that the carat is the measurement of weight for diamonds, this does not provide a useful means of understanding carat weight in relation to other weights. It is simple to understand that a heavy diamond is not going to be heavy in relationship to most items that we are familiar with handling daily, but this doesn't give you a good feel for the weights that you will be dealing with when you are looking into diamonds. This is all the more reason to have a good understanding of the relationships between carat weight and how you can better identify the rough value of a diamond through sight and feel.

"Points" is another term that you will hear to describe the weight of a diamond. The term "points" is used in the diamond industry to indicate diamond measurements that are lower than one carat. In the points measurement, one carat is divided into 100 points. Basically, if you are looking at a half-carat diamond, you may hear it being described as a 50-point diamond. Using the term '50 points' is simply another way of saying that the diamond is a 'half-carat' or 0.50 carats.

To place a carat next to a measurement scale most of us are familiar with, a carat is equivalent to approximately one seven thousandths of an ounce. This one relationship of two different types of weight measurement immediately demonstrates the small sizes that are being discussed when one is speaking of diamonds. To put a little more perspective on this, the largest rough diamond ever found, the Cullinan diamond from the Premier mine in South Africa, was an enormous 3,106 carats prior to cutting. This is a gigantic diamond, yet it is the equivalent of roughly three and a half pounds. Looking at it in such a light, you can see that even an enormous diamond, worth millions of dollars, is still fairly light in comparison to other precious commodities.

The following table will help to further illustrate the carat in comparison to other measurements of weight:

• 1 carat = 200 milligrams
• 1 carat = 1/5^th gram
• 1 carat = 0.20 grams
• 1 carat = 100 points
• 1 carat = 4 grains Troy
• 1 carat = 0.007 ounce
• 141.7 carats = 1 ounce

Another term of weight measurement that may be confusing is the term "Troy". The "Troy" is a measurement of weight that got its name from the French city of Troyes, which became an important trade city during the Middle Ages. The Troy unit of measurement was primarily used for precious metals, drugs and precious gems, such as diamonds. One Troy ounce is the equivalent of 31.1035 grams, or 480 grains.

The grain is the system of weight that was based on, simply enough, the wheat grain (or the barley grain in some ancient cultures). The grain was the equivalent of 1/4^th of a carat, or, more simply, one carat equaled approximately 4 grains. From this use of the grain, you can see that the ancients understood the need for a quantifiable and standard system of weight. The tiny weight measurements involved with the grain further demonstrates their understanding of the need for weight that could accurately and consistently give a weight measurement for diamonds.

As you are deciding on your carat size, remember that the heavier diamonds are not necessarily better than smaller, less weighty diamonds. A smaller diamond with excellent cut, clarity and color will be far more impressive and arresting to the eye than a diamond with a large carat weight that has a poor cut, clarity and/or color. To illustrate the size factor further, think of what you would find more impressive in a car: a large, clunky Oldsmobile, or a small, sleek, Corvette? The same goes for diamonds. There are times when bigger is better, but unless you can afford to have all of the factors going up in relationship with the diamond's carat weight, you are better off choosing the cut, clarity and color of the diamond that you want, and then choosing the carat weight that you can afford.

Another important point to be aware of is the factor of cut-off carat weights. These are also known as 'expense points' and having familiarity with them can not only save you money, but will also allow you to either reach or come close to the carat weight that you desire. Expense points refer to cut off points in carat weight where the cost can rise or decline exponentially. These points are at certain carat weights, such as the following: .50, .75, .90, 1, 1.5, 2 and so on. By staying just below these points, you can have a diamond that is negligibly less in weight, but notably less in expense. What this means is quite simple. If you are looking for a one-carat diamond, rather than choosing a diamond of one-carat or slightly larger choose a diamond that falls just below one carat, such as a .95 diamond. There will be no identifiable difference, especially once the diamond is set, and you could save a large amount of money.

Carat weight plays an important role in the pricing of your diamond, but it should not be the factor that outweighs all others. Each factor should be weighed alongside all others, but carat weight is the first that you can easily decrease in, without sacrificing the overall appearance of the diamond. In the end, the primary function of the diamond is an issue of aesthetics: you want the most beautiful diamond you can attain. It should be towards this goal that you assess all of the factors involved, in order to achieve the balance that will provide you with the diamond that will prove to be the perfect diamond for you.

Carat Expense Guide

There are many factors to take into account when you are looking into buying a diamond, and the carat weight is one of the most important. Within the diamond industry, carat weight is priced through a number of factors, including the color and clarity as weighed against, and with, various carat weights. All of this is published in the Rapaport Report, and diamond dealers use this as a price guide for the per carat price for diamonds.

The Rapaport Report: This is a monthly-published diamond trade paper that offers current per-carat pricing for diamonds. This diamond price report arrives at diamond pricing based on color, clarity and carat weight. Using the pricing guide will give you an idea of the current rate of a particular weight and color of diamond. What it cannot give you is an accurate price for an individual diamond. This is merely a tool for those in the industry to have an idea of what the approximate price for a particular type of diamonds is, and using it will allow you to know the price range that you should expect to see.

There are some problems in using the Rapaport Report as your sole means of determining a diamond's price range. One of the most obvious of these is that the report does not take an individual diamond's unique characteristics into account. While it does account for the clarity, color, the carat weight and certain other important aspects, this can hardly show the entire picture. The report cannot tell you if a particular diamond has a cut that is amenable to your personal tastes, nor can it account for the reflection of the diamond's clarity and color, once set and sitting on your finger. In the end, it is useful to be familiar with the Rapaport Report, but it should not be a strong deciding factor in your choice of diamonds. Use it simply to make certain that you know what price range you should expect, and then look for the dealer who offers their diamonds at a discounted price from that found in the Rapaport Report.