Rough retail range
$4,900 to $9,100
Around $7,000 per carat for a 1.00 ct G VS2 excellent cut natural round brilliant.
This is an estimate, not an appraisal. Real prices move with the market, the shape, fluorescence, the certificate that comes with it and who is selling. Fancy shapes typically run 10 to 30 percent below round for the same grades. Lab grown pricing in particular has been falling fast, so treat that number as the roughest of the two. For anything you are buying, selling or insuring, get it appraised.
How diamond pricing actually works
The trade runs on price-per-carat sheets. A dealer looks up the grade combination, finds a price per carat, multiplies by the weight, and then discounts or adds from there based on things the sheet does not capture: the exact certificate, fluorescence, how the stone actually looks.
The critical thing to understand is that price per carat is not fixed. It climbs steeply with weight, because large rough crystals are far rarer than small ones.
| Weight | Roughly this many times the 1ct price per carat |
|---|---|
| 0.50 ct | About half |
| 0.90 ct | About 85 percent |
| 1.00 ct | Baseline |
| 1.50 ct | About 1.35x |
| 2.00 ct | About 1.85x |
| 3.00 ct | About 2.6x |
Which produces the effect people find counterintuitive: a two carat stone typically costs three to four times a one carat of the same quality, not twice.
The 0.90 carat trick
Prices jump at the round numbers because that is where demand piles up. Almost nobody shops for a 0.92 carat diamond, so cutters push stones to land at 1.00 and buyers pay for the number.
A 0.90 carat stone is about 6.2mm across against 6.5mm for a full carat. Nobody has ever noticed that difference on a hand, and the price gap can be substantial. It is one of the few places in this business where being slightly unfashionable saves real money.
What the calculator cannot see
Shape, for one. It assumes a round brilliant, which is the most expensive shape per carat. Ovals, pears, cushions and emeralds typically run 10 to 30 percent lower for identical grades, because they waste less rough and demand is thinner.
It also cannot see fluorescence, which can discount a high colour stone or quietly improve a low one, or the difference between a GIA certificate and one from a lab with looser standards. Two stones with the same grades on paper from different labs are not the same stone.
Not sure what grades you are looking at?
Photograph the stone and the app reads its visible characteristics and gives you an estimated value range. Free on iOS and Android.
Frequently asked questions
How accurate is this calculator?
Why does price per carat jump so much with size?
What will a jeweller actually pay me?
Why are lab grown prices so much lower?
Worth being clear: everything here, and the app itself, is an educational reference. At-home tests narrow things down, they do not certify a stone. Before you buy, sell or insure anything of real value, get it looked at by a certified gemologist or an independent appraiser.