How much does a 3.00 to 4.99ct J SI2 lab grown radiant diamond cost?

As of September 2026, 3.00 to 4.99ct J SI2 lab grown radiant diamonds typically cost £5,501 GBP to £29,469 GBP, with a median price of £14,576 GBP. There are currently 21 diamonds matching this specification available across retailers.

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

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3.00 to 4.99ct J SI2 Lab Grown Radiant

Quick answer

As of September 2026, there are 21 lab grown radiant diamonds with J colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £5,501 GBP to £29,469 GBP, with a median of £14,576 GBP. At least 6 retailers stock this exact specification. Half of all listings fall between £2,000 GBP and £6,410 GBP per carat. The same specification in natural form lists at a median of about £5,852 GBP per carat.

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

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Radiant lab grown stones in the index: 473 USD per carat, -12.5% month on month. See the full index release

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

Last updated: September 2026

Available

Lowest Price

£5,176 GBP

Highest Price

£30,555 GBP

Average Price

£15,406 GBP

Market Intelligence

Retailers Selling

Price Spread

172.8%

Price Range

Price per carat distribution across retailers

$3,449/ct

10th Percentile

$2,449

Median

$3,449

90th Percentile

$10,668

Score Distribution

21 diamonds scored across 2 quality tiers

Good

5 (23.8%)

Average

16 (76.2%)

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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