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 £18,110 GBP to £62,178 GBP, with a median price of £30,397 GBP. There are currently 55 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 32%. 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 55 natural radiant diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £18,110 GBP to £62,178 GBP, with a median of £30,397 GBP. At least 47 retailers stock this exact specification, and 34% of the stones appear at more than one of them, with an average price spread of 32%. Half of all listings fall between £6,285 GBP and £8,719 GBP per carat. Over the last 30 days the median price moved -0.5% and the number of listings moved +10.5%.

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

£7,612 GBP

Highest Price

£100,954 GBP

Average Price

£34,314 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

33.9%

Price Spread

32.1%

30-Day Price Trend

-0.5%

30-Day Supply Change

+10.5%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$10,166/ct

10th Percentile

$6,351

Median

$10,166

90th Percentile

$13,242

Score Distribution

192 diamonds scored across 4 quality tiers

Excellent

33 (17.2%)

Very Good

35 (18.2%)

Good

23 (12.0%)

Average

101 (52.6%)

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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