Diamonds are priced per carat, and the price per carat rises with size and quality. A two-carat diamond usually costs far more than two one-carat diamonds of the same grade, because large stones are rarer. The 4Cs set the band a stone falls in, and cut quality, fluorescence, the grading lab and market conditions move it within that band. Retail adds further costs on top of the wholesale price.
Price per carat
The trade quotes diamond prices as a figure per carat. To get the total price, multiply the per-carat figure by the weight. A 1.20-carat stone at a given per-carat price costs 1.2 times that figure.
The per-carat price is not fixed across sizes. It steps up at certain weights because larger rough is rarer. A 1.00-carat stone carries a higher per-carat price than a 0.90-carat stone of the same color and clarity. The jump at 1.00 carat is the best known, but jumps also happen at 0.50, 0.70, 1.50, 2.00, 3.00 and other weights. The trade calls these "magic sizes."
Stones just under a threshold, such as 0.95 carat, often cost noticeably less than a full carat while looking almost identical once set. The carat weight guide explains diameter and spread, which also affect how big a stone looks.
How the 4Cs combine
Each of the 4Cs moves the price, but they do not add up neatly.
- Carat sets the size bracket and the base per-carat price.
- Color shifts price at each step on the D to Z scale. D, E and F colorless stones cost the most.
- Clarity shifts price by grade from Flawless to I3. Higher grades cost more, but the difference between grades the eye cannot see can be large.
- Cut affects price more for round brilliants than fancy shapes, because labs give rounds a formal cut grade.
The Cs interact. In small stones, color and clarity differences are hard to see and affect price less. In large stones, the same differences show more and widen the price gap between grades. A rare combination such as D color and Flawless clarity commands a premium beyond what either grade alone would suggest.
Shape and cut
Round brilliants usually cost more per carat than fancy shapes of the same grades. Cutting a round from rough loses more weight, and demand for rounds is high. Pears, ovals, cushions, emerald cuts and princesses often come in lower per carat. See how diamonds are cut for the yield trade-off.
Within rounds, cut grade matters. An Excellent cut stone generally costs more than a Good cut stone of the same weight and grades. A poorly cut stone may carry extra weight in a thick girdle or deep pavilion, which makes it cheaper per carat but smaller face-up for its weight.
Other factors
Several other things affect price:
- Fluorescence. Strong blue fluorescence in near-colorless stones often lowers the price, while in lower colors it can make a stone look whiter.
- Grading lab. Stones graded by labs with stricter standards tend to bring higher prices than stones of the same stated grades from labs seen as more lenient. See diamond grading labs.
- Treatment. Laser-drilled, fracture-filled or color-treated diamonds sell at a discount to untreated stones of similar appearance. See diamond treatments.
- Fancy color. Natural fancy colored diamonds follow their own pricing, where hue and saturation matter most.
Wholesale price lists
The diamond trade has long used published price lists as a reference for polished stones. The best-known is the Rapaport Diamond Report, published since the late 1970s, which gives asking prices per carat in grids sorted by shape, size, color and clarity. Other lists and trading platforms also publish benchmark data.
Dealers usually negotiate from a list price, quoting a percentage below or above it. Lists are reference points, not final prices. Actual transaction prices can be well below the list figure, depending on cut quality, lab, fluorescence and demand.
Retail markup
A diamond passes through several hands between the mine and the buyer: miners, rough dealers, cutters, polished wholesalers, jewelry manufacturers and retailers. The diamond pipeline describes each stage. Each adds a margin to cover costs and profit.
Retail markup varies widely. Physical stores carry rent, staff and inventory, and their markups tend to be higher than online sellers that hold less stock or list stones held by suppliers. Markup can also depend on the setting, brand and services such as warranties, resizing and trade-in policies. There is no single standard figure.
Natural and lab-grown pricing
Lab-grown diamonds have the same physical properties as natural diamonds and are graded on the same 4Cs. Their prices are far lower than natural diamonds of matching grade, and the gap widened through the late 2010s and 2020s as production grew and manufacturing costs fell.
Lab-grown prices have historically fallen faster and further than natural prices, and lab-grown stones have very limited resale value. Buyers should check reports and inscriptions to confirm whether a stone is natural or lab-grown, since the price difference is large.
A short price history
Through most of the 20th century, De Beers controlled much of the world's rough supply and managed release to keep prices steady. That single-channel era ended in the 2000s, and natural diamond prices have moved more with demand and supply since. The history of the diamond trade covers these changes.
Frequently asked questions
Why does a 2-carat diamond cost more than twice a 1-carat diamond?
The per-carat price rises with size because larger rough is rarer. A 2-carat stone carries a higher price per carat as well as twice the weight.
Is it cheaper to buy a diamond just under 1 carat?
Usually. Stones such as 0.90 to 0.99 carat often cost noticeably less per carat than 1.00-carat stones of the same grades and look nearly the same size.
Which of the 4Cs affects price the most?
Carat usually has the largest effect, followed by color and clarity. Cut quality has a strong effect on round brilliants.
Why are lab-grown diamonds cheaper?
Production costs have fallen and supply can grow as needed, while natural diamonds come from a limited supply of rough. Both have the same physical properties.