How much does a 3.00 to 4.99ct G SI2 lab grown round diamond cost?

As of October 2026, 3.00 to 4.99ct G SI2 lab grown round diamonds typically cost £568 GBP to £1,557 GBP, with a median price of £908 GBP. There are currently 9 diamonds matching this specification available across retailers.

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

About 18% 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.

3.00 to 4.99ct G SI2 Lab Grown Round

Quick answer

As of October 2026, there are 9 lab grown round diamonds with G colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £568 GBP to £1,557 GBP, with a median of £908 GBP. At least 25 retailers stock this exact specification, and 18% of the stones appear at more than one of them, with an average price spread of 62%. Half of all listings fall between £188 GBP and £359 GBP per carat. The same specification in natural form lists at a median of about £9,796 GBP per carat. Over the last 30 days the median price moved +17.4% and the number of listings moved +0.1%.

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 lab grown stones in the index: 414 USD per carat, -5.0% 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

£280 GBP

Highest Price

£3,278 GBP

Average Price

£1,017 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

17.6%

Price Spread

61.9%

30-Day Price Trend

+17.4%

30-Day Supply Change

+0.1%

Volatility (30d)

0.07

Price Range

Price per carat distribution across retailers

$369/ct

10th Percentile

$144

Median

$369

90th Percentile

$665

Score Distribution

55 diamonds scored across 4 quality tiers

Excellent

7 (12.7%)

Very Good

2 (3.6%)

Good

4 (7.3%)

Average

42 (76.4%)

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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