DIAMOND CARAT WEIGHT
he term carat (ct) refers to the weight of a diamond. To break it down, one carat equals 200 milligrams (0.20 grams), which is divided into 100 points for precision. Therefore, a diamond weighing one-tenth of a carat may be referred to as 0.10 carats or “10-points”. It is important to note that “carat” (abbreviated ct), in this case, is not the same as “karat” (abbreviated K or kt). Although both are units of measurement used in jewelry, carat is a measure of gemstone weight, while karat is a measure of gold purity.
Diamond carat weight is just one determining factor when it comes to the stone’s overall appearance and worth. The other factors include color, clarity, and cut. Together, they constitute the “4Cs” of diamond appraisal, which experts use to evaluate diamond quality.
Contrary to popular belief, a diamond’s carat weight does not necessarily reflect its actual size. For example, two diamonds of equal carat weight may appear slightly different in mm size when viewed from above, depending on their other attributes.
When evaluating the millimeter (mm) size of a diamond, the top diameter and cut grade of the stone are taken into account, along with carat weight. Together these are known as the diamond’s dimensions. The distance across the top of the diamond is crucial since this is how diamonds are generally viewed once set in jewelry. The cut (i.e., the diamond shape) similarly affects the stone’s perceived size. A well-proportioned diamond maximizes light performance, making it appear larger in a jewelry piece.
Market Retail Price
Diamond prices tend to jump by half-carats, making more than a slight difference. You will often find that the price difference between a 0.9 and 1.00 ct diamond (or 0.75 ct and 0.50 ct) is much larger than the difference between a 0.8 and 0.9 ct (or 1.25 ct and 1.50 ct) diamond. Furthermore, diamond prices increase exponentially rather than linearly. The scarcity of large gem-quality rough diamonds, for instance, means that a single good cut 2.00 ct stone will cost much more than two 1.00 ct diamonds. It is also not guaranteed that two diamonds of the same carat weight (i.e., equal carat weight) will be valued at the same amount. There are other factors involved too.
WEIGHT & CARAT DIAMOND SIZE CHART
This carat weight and diamond size chart describes the carat weight of a diamond along with its width in millimeters. This diamond size chart gives you an idea of the ratio of the different carat weights to a diamond’s physical (mm) size.
Frequently Asked Questions About Diamond Carat Weight
The Maoussaieff Red Diamond. Discovered in Brazil in the 199os and formerly known as the Red Shield, the Maoussaieff Red Diamond is the largest red-colored diamond in existence. Weighing 5.11 carats, it was displayed at the Smithsonian Institution in 2003 and 2005 as one of the most incredible diamonds in the world. With its brilliant triangular cut, this diamond is estimated at $8 million.
The Heart of Eternity. This Fancy Vivid Blue diamond was mined in South Africa. It was cut into a heart shape by the Steinmetz Group and is priced at $16 million, or thereabouts.
The Graff Pink. A rare pink 24.78 ct diamond sold for $46 million at an auction in Geneva, Switzerland, in 2010.
The Wittelsbach Diamond. This Fancy Deep-Blue diamond with internally flawless clarity has been associated with Spanish and German royalty since its arrival in Europe in the 1600s. It was bought for $24.3 million in 2008.
The Winston Blue. Named after the celebrity jeweler Harry Winston, this Fancy Vivid Blue diamond was mined in South Africa. Pear-shaped and internally flawless, this jewel was bought for an estimated $23.8 million in 2014, setting a new world record for the most expensive blue diamond ever sold.
The Pink Star. Mined in South Africa in 1999 and originally named the Steinmetz Pink, the Pink Star is the world’s largest Fancy Vivid Pink diamond. Bought in Sotheby’s Auction in 2017 over a telephone bid for $71.2 million, this internally flawless 59.60 ct oval-shaped gem was then renamed the CTF Pink Star (in honor of the buyer’s late father).
The Centenary Diamond. Weighing 119.8 grams (or 599 ct) in its rough form, this massive gem was later cut into a modified heart shape, which reduced its carat weight to 273.85 ct. Nevertheless, the entire process took a team of experts 154 days to accomplish. The diamond was insured for over $100 million at the time of its unveiling in 1991, but it has never been publicly appraised.
The Hope Diamond. Priced at $200-$350 million, this 45.52 ct Fancy Dark Grayish-Blue antique cushion cut diamond is believed to have been discovered in India in the 1600s. It was bought by King Louis XIV in 1668 and then stolen, along with the crown jewels, during the looting that took place in 1792 after King Louis’s demise. Later, it resurfaced in London and was purchased by Harry Winston in 1949, who donated it to the Smithsonian Institution. Unfortunately, because its previous owners all met with ill fate, the Hope Diamond is rumored to be cursed.
The Cullinan Diamond. Also known as the Star of Africa, the Cullinan Diamond is the largest rough diamond of gem-quality to have ever been found. It was discovered in Cullinan, South Africa, in 1905 and was gifted to King Edward VII. Valued at around $2 billion, it weighed approximately 621.35 grams (3,106.75 ct) before it was cut into nine “smaller” stones, the largest of which is the Cullinan I at 530.2 ct.
The Koh-I-Noor. This colorless oval-shaped gem weighing 105.6 ct is steeped in mystery and legend. It was found in India in the 1300s and is also called the Mountain of Light and the Diamond of Babur. Currently, the stone forms part of the British crown jewels and is set in the crown of the Queen Mother.Here are the ten most expensive diamonds in the world, according to size, sparkle, clarity, and ct weight:
Alternatively, if you are buying a diamond from a shop, you can ask to see its diamond certificate. Also known as a diamond grading report, it confirms the identity and quality of the gem, giving you the assurance that you are getting what you pay for.
As you can see, there is a considerable amount of variation in diamond carat size for engagement rings. Thus, there are no set rules when it comes to the “ideal” proportions of a center stone for an engagement ring – it is more a question of personal preference and price.
Also, bear in mind that engagement ring settings have an effect on the appearance of the stone and that you need to consider what the finished piece will look like on your partner’s finger. If you are unsure about the design, ask your jeweler for advice on the different weights and settings. Alternatively, you could consult a diamond carat guide or carat weight chart/table.
-round diamond/round brilliant cut (the round diamond or round cut is the most “popular” cut for engagement rings)
-princess (or square) cut
Other cuts that aren’t often seen and that are patented to specific brands include the Asprey, eighty-eight, Ashoka, jubilee, lily, princess plus, royal Asscher, bead, and criss cuts. All these shapes (including the ones above) come in different ct sizes for diamonds and other st