The 4th C, “Carat Weight” is probably the easiest to understand. Put the diamond on a scale, and weigh it! A carat is one fifth of a gram, and is the measure of weight used exclusively for gemstones. The name derived historically from the weight of a carob seed. Carat should never be confused with karat, which is a measure of metal purity. “Carat Weight” is one of the rarity-in-nature factors that affect the price of a diamond.

Let us be clear, it is very important not to confuse Carat weight and apparent visual size. This points us back to the primacy of the 1st C, “Cut”. Diamonds, being 3 dimensional, can appear either larger, or smaller, than they actually weigh by being cut either too shallow or too deep. Both these type cuts will “leak light” and appear relatively lifeless under good lighting. Cutters tend to cut too deeply in order to retain weight, so be mindful that the actual weight matches the apparent size. Well cut stones will return light “edge to edge” revealing the true diameter of the stone.

All other things being equal, the greater the Carat weight, the rarer the diamond is, and therefore the more expensive it will be. This is especially true where the weight crosses the threshold of a whole number.

Carat weight X Price per Carat = Total Price

To choose the ideal “Carat Weight” for you, consider the following:

• The wearer’s personal style and preferences
• The wearer’s finger size (the smaller the finger, the larger the apparent size)
• The nature of the setting, if it has been selected
• The buyer’s budget