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

As of October 2026, 3.00 to 4.99ct G SI2 lab grown marquise diamonds typically cost £289 GBP to £1,679 GBP, with a median price of £1,144 GBP. There are currently 1 diamonds matching this specification available across retailers.

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

About 23% of these diamonds are available at multiple retailers, with an average price spread of 90%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct G SI2 Lab Grown Marquise

Quick answer

As of October 2026, there are 1 lab grown marquise diamonds with G colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £289 GBP to £1,679 GBP, with a median of £1,144 GBP. At least 19 retailers stock this exact specification, and 23% of the stones appear at more than one of them, with an average price spread of 90%. Half of all listings fall between £151 GBP and £429 GBP per carat. The same specification in natural form lists at a median of about £11,080 GBP per carat. Over the last 30 days the median price moved +26.3% and the number of listings moved +36.9%.

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

3.03ct Marquise G SI2, IGI, grade A, from £260 GBP

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. Marquise lab grown stones in the index: 485 USD per carat, -3.2% 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

£260 GBP

Highest Price

£1,682 GBP

Average Price

£1,101 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

23.1%

Price Spread

89.7%

30-Day Price Trend

+26.3%

30-Day Supply Change

+36.9%

Volatility (30d)

0.08

Price Range

Price per carat distribution across retailers

$415/ct

10th Percentile

$137

Median

$415

90th Percentile

$788

Score Distribution

8 diamonds scored across 2 quality tiers

Excellent

2 (25.0%)

Average

6 (75.0%)

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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