How much does a 0.75 to 0.99ct G SI1 lab grown marquise diamond cost?

As of November 2026, 0.75 to 0.99ct G SI1 lab grown marquise diamonds typically cost £214 GBP to £492 GBP, with a median price of £352 GBP. There are currently 9 diamonds matching this specification available across retailers.

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

About 16% of these diamonds are available at multiple retailers, with an average price spread of 56%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct G SI1 Lab Grown Marquise

Quick answer

As of November 2026, there are 9 lab grown marquise diamonds with G colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £214 GBP to £492 GBP, with a median of £352 GBP. At least 22 retailers stock this exact specification, and 16% of the stones appear at more than one of them, with an average price spread of 56%. Half of all listings fall between £276 GBP and £475 GBP per carat. The same specification in natural form lists at a median of about £2,155 GBP per carat. Over the last 30 days the median price moved +0.9% and the number of listings moved 0.0%.

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: November 2026

Available

Lowest Price

£207 GBP

Highest Price

£884 GBP

Average Price

£368 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

15.5%

Price Spread

56.2%

30-Day Price Trend

+0.9%

30-Day Supply Change

0.0%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$475/ct

10th Percentile

$197

Median

$475

90th Percentile

$731

Score Distribution

20 diamonds scored across 3 quality tiers

Very Good

4 (20.0%)

Good

8 (40.0%)

Average

8 (40.0%)

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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