How much does a 3.00 to 4.99ct I SI2 natural radiant diamond cost?

As of October 2026, 3.00 to 4.99ct I SI2 natural radiant diamonds typically cost £18,222 GBP to £62,876 GBP, with a median price of £30,650 GBP. There are currently 62 diamonds matching this specification available across retailers.

Where can I find the best price on a I SI2 radiant diamond?

About 34% of these diamonds are available at multiple retailers, with an average price spread of 40%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI2 Natural Radiant

Quick answer

As of October 2026, there are 62 natural radiant diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £18,222 GBP to £62,876 GBP, with a median of £30,650 GBP. At least 45 retailers stock this exact specification, and 34% of the stones appear at more than one of them, with an average price spread of 40%. Half of all listings fall between £5,428 GBP and £8,235 GBP per carat. Over the last 30 days the median price moved -0.5% and the number of listings moved +9.3%.

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. Radiant natural stones in the index: 3,091 USD per carat, +13.2% 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

Lowest Price

£7,650 GBP

Highest Price

£101,576 GBP

Average Price

£34,928 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

34.3%

Price Spread

40.0%

30-Day Price Trend

-0.5%

30-Day Supply Change

+9.3%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$9,350/ct

10th Percentile

$5,853

Median

$9,350

90th Percentile

$12,226

Score Distribution

213 diamonds scored across 4 quality tiers

Excellent

39 (18.3%)

Very Good

45 (21.1%)

Good

27 (12.7%)

Average

102 (47.9%)

Find Your Diamond

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Consider Instead

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J SI2J colour is visually identical to I to the naked eye

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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