How much does a 3.00 to 4.99ct J SI1 lab grown round diamond cost?

As of September 2026, 3.00 to 4.99ct J SI1 lab grown round diamonds typically cost £737 GBP to £29,970 GBP, with a median price of £4,196 GBP. There are currently 209 diamonds matching this specification available across retailers.

Where can I find the best price on a J SI1 round diamond?

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3.00 to 4.99ct J SI1 Lab Grown Round

Quick answer

As of September 2026, there are 209 lab grown round diamonds with J colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £737 GBP to £29,970 GBP, with a median of £4,196 GBP. At least 22 retailers stock this exact specification. Half of all listings fall between £655 GBP and £1,982 GBP per carat. The same specification in natural form lists at a median of about £7,060 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. Round lab grown stones in the index: 438 USD per carat, -14.1% 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

209

Lowest Price

£483 GBP

Highest Price

£60,212 GBP

Average Price

£8,995 GBP

Market Intelligence

Retailers Selling

Price Spread

87.0%

Price Range

Price per carat distribution across retailers

$2,059/ct

10th Percentile

$422

Median

$2,059

90th Percentile

$3,166

Score Distribution

209 diamonds scored across 4 quality tiers

Excellent

40 (19.1%)

Very Good

100 (47.8%)

Good

43 (20.6%)

Average

26 (12.4%)

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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