Diamond Carat Weight
Carat value is one of the Four Cs, the four most important factors that determine the price of a diamond. In simple terms, big lumps of ice usually cost more!
What Is A Carat?
Carats are a measure of the mass and hence weight of a diamond - in effect, the larger the stone the more carats it will contain. The rarity of natural stones tends to increase exponentially with their carat weight. Even if a raw diamond is large it will almost always need to be cut to a pleasing shape, losing some of its mass and reducing the carat ratingNote though that because of the wide variety of cuts it's possible for a diamond that at first seems larger than another to actually weigh less. Some clever cuts, especially the modern ones, are very good at making a gem seem larger than it actually is.
If you buy a piece of jewelry such as a necklace or ring that contains multiple diamonds it's common for the total carat weight (cttw) of all the stones to be given, perhaps as well as the individual weights of the most important stones.
So how heavy is one carat? Not very. A carat is a very small unit of weight indeed. One carat (1 ct) is equal to 200 milligrams. That's approximately seven thousandths of an ounce!
Carats vs Karats
It's important not to confuse diamond carats - a measure of weight - with gold karats, which are a measure of purity. The two measurements have nothing in common other than confusingly similar names.