How much does a 1.50 to 1.99ct I I1 natural round diamond cost?

As of October 2026, 1.50 to 1.99ct I I1 natural round diamonds typically cost £1,905 GBP to £6,777 GBP, with a median price of £4,014 GBP. There are currently 289 diamonds matching this specification available across retailers.

Where can I find the best price on a I I1 round diamond?

About 27% of these diamonds are available at multiple retailers, with an average price spread of 62%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct I I1 Natural Round

Quick answer

As of October 2026, there are 289 natural round diamonds with I colour and I1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £1,905 GBP to £6,777 GBP, with a median of £4,014 GBP. At least 29 retailers stock this exact specification, and 27% of the stones appear at more than one of them, with an average price spread of 62%. Half of all listings fall between £1,642 GBP and £3,105 GBP per carat. The same specification in lab grown form lists at a median of about £453 GBP per carat. Over the last 30 days the median price moved -5.5% and the number of listings moved +5.7%.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, September 2026: natural diamonds at 2,335 USD per carat and lab-grown at 443 USD per carat, a natural to lab ratio of 5.3 to 1. Round natural stones in the index: 2,248 USD per carat, +7.6% month on month. See the full index release

Figures come from current listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: October 2026

Available

289

Lowest Price

£860 GBP

Highest Price

£12,622 GBP

Average Price

£4,296 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

27.4%

Price Spread

62.2%

30-Day Price Trend

-5.5%

30-Day Supply Change

+5.7%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$3,132/ct

10th Percentile

$1,504

Median

$3,132

90th Percentile

$5,162

Score Distribution

733 diamonds scored across 4 quality tiers

Excellent

70 (9.5%)

Very Good

147 (20.1%)

Good

125 (17.1%)

Average

391 (53.3%)

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Consider Instead

Save money without compromising on what matters. These alternatives are visually similar but cost less.

J I1J colour is visually identical to I to the naked eye

Save 18%

Lab-Grown I I1Same specifications, lab-grown origin

Save 81%

Related Specifications

D IF D VVS1 D VVS2 D VS1 D VS2 D SI1 E IF E VVS1 E VVS2 E VS1 E VS2 E SI1 F IF F VVS1 F VVS2 F VS1 F VS2 F SI1 G IF G VVS1 G VVS2 G VS1 G VS2 G SI1 H IF H VVS1 H VVS2 H VS1 H VS2 H SI1 I IF I VVS1 I VVS2 I VS1 I VS2 I SI1