Diamonds are weighed in “carats” or “points” prior to being set into jewelry. Carats and points are both units of measure, just like pounds or ounces. A one carat diamond is equivalent to one fifth of a gram.
Carat (spelled with a ‘C’) is often confused with karat (spelled with a ‘K’), which is used when referring to the percentage of gold content in jewelry as in “fourteen-karat-gold. “ There are actually three homonyms; the vegetable (carrot); gold content (karat); and diamond weight (carat).
A one carat diamond has 100 points — just like one dollar has 100 cents. So, a ¼ carat diamond is approximately 23 points to 28 points; a 5/8 carat diamond is approximately 58 points to 69 points; and a two carat diamond is exactly or near 200 points, and so on. “Points” is an especially confusing term because people often think of points as “points-of-light” from within the diamond (called scintillation or sparkle) or the “points” where a diamond’s different surfaces meet. Nope, it’s none of the above. “Points” are just a unit of weight.
Why do we use carat instead of, for instance, grams? Because hundreds of years ago diamonds were weighed using a simple balance. Carob seeds were a handy unit of measure due to their consistent size and weight relative to diamonds. “Carat” comes from the word carob, and the old “carob” tradition stuck. Think of it just like the United States not yet converted to the more modern metric system. In case you were wondering, and you’re about average, you’d weigh 86 million carats!
Don’t get too hung up on what a diamond weighs because weight doesn’t always reflect its size. Confused? Don’t be. You see, in most cases, the secret to unleashing the beauty from within a diamond, is to cut away valuable weight from the very bottom of the raw stone. And if this weight isn’t trimmed off you end up paying for weight that doesn’t make the diamond look bigger and detracts from its beauty. Think of it like a butcher who sells you a steak without trimming the fat.
It’s like the difference between quantity versus quality. So, in actuality, you want to compare diamonds by its diameter (or dimensions viewed from the top), not its weight.
How does size affect price?
Diamonds are priced like lobsters (by the pound), except that each price jump is even more dramatic. The larger they are, the more expensive per pound; the same is true for diamonds. A half-carat diamond selling for $1900 would cost about $8700 if it were a one carat with identical characteristics. Pricing can also increase significantly with a little bit of additional weight, as when going from 99 points to a one carat (one hundred points).
Also, pricing can increase a lot for just a little bit of additional weight as when going from 99 points to a one carat (one hundred points).
Perrywinkle’s uses a Swiss-made diamond scale which provides your diamond weight to the nearest tenth of a point and then it’s weighed again, in front of you, prior to being set into its ring. For example, a diamond that weighs 97 points is listed as 97.6 points. The weight is then documented on a unique, individually-numbered Perrywinkle’s Diamond Grading Report. The Diamond Grading Report Number is then microscopically laser- inscribed on the outer edge of the diamond (38 points or 3/8ths of a carat and larger). It is not unheard of, especially with chain stores, to see the weight of a diamond merely estimated.