Diamond Carat Weight Education: What You Should Know

The size of a diamond is one of its most noticeable characteristics. To measure the size of a diamond, carat weight is used. Over time, the definition of a carat has changed, but since 1913, the international standard has been 200 milligrams, or 1/5 of a gram. To further delineate carat weight, a single carat is divided into 100 “points”. As an example, a 25 point diamond weighs a quarter of a carat and a 50 point diamond weighs half a carat.

It is correct to refer to a diamond as either three quarters of a carat or a 75 point stone; although jewelers usually express diamond weight in carats when the weight is a carat or above and in points when the weight is less than a carat. It is also important to note that “carat total weight”
(Ct. T. W.) describes the combined total weight of all the stones in a piece of jewelry.

Since larger stones are found much less frequently than smaller ones, diamond prices tend to rise with carat weight. Even with all other factors being equal, for example, a .50 ct diamond will cost more than twice that of a .25 ct and a single 2 ct diamond will cost much more than two 1 ct diamonds of the same quality. Furthermore, because they are so desirable, a full carat diamond will be priced significantly higher than a .95 ct stone, even though the .95 ct stone is only somewhat more expensive than a .90 ct stone.

All that said, bigger is certainly not always better. The ultimate value of a diamond is determined by how well the “4Cs” of cut, clarity, color and carat weight all come together. No one factor outweighs the others and all of the factors together must be taken into consideration to truly determine a diamond’s value.