How much does a 5.00ct+ G SI1 lab grown round diamond cost?

As of October 2026, 5.00ct+ G SI1 lab grown round diamonds typically cost £640 GBP to £5,021 GBP, with a median price of £1,517 GBP. There are currently 109 diamonds matching this specification available across retailers.

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

About 53% of these diamonds are available at multiple retailers, with an average price spread of 81%. A comparison tool like Carat Hunter lets you see all the prices side by side.

5.00ct+ G SI1 Lab Grown Round

Quick answer

As of October 2026, there are 109 lab grown round diamonds with G colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run £640 GBP to £5,021 GBP, with a median of £1,517 GBP. At least 27 retailers stock this exact specification, and 53% of the stones appear at more than one of them, with an average price spread of 81%. Half of all listings fall between £186 GBP and £392 GBP per carat. The same specification in natural form lists at a median of about £18,491 GBP per carat. Over the last 30 days the median price moved -12.3% and the number of listings moved +29.1%.

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

109

Lowest Price

£442 GBP

Highest Price

£20,880 GBP

Average Price

£2,255 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

52.5%

Price Spread

81.4%

30-Day Price Trend

-12.3%

30-Day Supply Change

+29.1%

Volatility (30d)

0.03

Price Range

Price per carat distribution across retailers

$338/ct

10th Percentile

$178

Median

$338

90th Percentile

$759

Score Distribution

211 diamonds scored across 4 quality tiers

Excellent

88 (41.7%)

Very Good

17 (8.1%)

Good

45 (21.3%)

Average

61 (28.9%)

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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