A carat is the unit of measurement used specifically when weighing gems and diamonds. The carat is derived from a “carob”, as in carob seed, that served as the standard counter weight for objects in ancient times prior to the invention of grams or ounces. In early times, precious metals and stones were weighed against carob seeds to distinguish their weight. If a stone balanced out against 3 carob seeds, it was said to weigh 3 seeds. Over time, that stone was said to weigh 3 carobs and finally, in today’s modern measurement, 3 carats.
Carat is often misunderstood for the size of the diamond based on its visual size, instead of its weight. All diamonds and gemstones contain different densities, which is why you cannot measure the true size of the stone based on its physical measurements. Typically, a 1 carat diamond will measure approximately 6.5 mm round, whereas a 1 carat sapphire will measure closer to 6.0 mm round.
Total carat weight is a term you will hear often in the jewelry industry. This is a phrase used to differentiate the total weight of all the diamonds or various gemstones within a piece of jewelry. For example, if your engagement ring has a 2.0 carat diamond center stone, and 1.0 carat of accent diamonds throughout the ring setting, it would be said that your engagement ring contains 3.0 total carat weight.
When evaluating a diamond, most will immediately focus on its carat weight to distinguish its value, but its carat weight is complimentary to the cut of the diamond itself.Diamond Size to Carat Chart
Your diamond may differ from the printout in length/width ratio, table, and depth.