How much does a 3.00 to 4.99ct F SI1 lab grown marquise diamond cost?

As of October 2026, 3.00 to 4.99ct F SI1 lab grown marquise diamonds typically cost £281 GBP to £2,538 GBP, with a median price of £1,141 GBP. There are currently 84 diamonds matching this specification available across retailers.

Where can I find the best price on a F SI1 marquise diamond?

About 28% of these diamonds are available at multiple retailers, with an average price spread of 117%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct F SI1 Lab Grown Marquise

Quick answer

As of October 2026, there are 84 lab grown marquise diamonds with F colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £281 GBP to £2,538 GBP, with a median of £1,141 GBP. At least 31 retailers stock this exact specification, and 28% of the stones appear at more than one of them, with an average price spread of 117%. Half of all listings fall between £188 GBP and £597 GBP per carat. The same specification in natural form lists at a median of about £14,389 GBP per carat. Over the last 30 days the median price moved +26.1% and the number of listings moved +39.7%.

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. 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

£270 GBP

Highest Price

£4,612 GBP

Average Price

£1,265 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

28.4%

Price Spread

116.9%

30-Day Price Trend

+26.1%

30-Day Supply Change

+39.7%

Volatility (30d)

0.09

Price Range

Price per carat distribution across retailers

$469/ct

10th Percentile

$150

Median

$469

90th Percentile

$1,125

Score Distribution

176 diamonds scored across 4 quality tiers

Excellent

41 (23.3%)

Very Good

21 (11.9%)

Good

31 (17.6%)

Average

83 (47.2%)

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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