How much does a 1.00 to 1.49ct G SI1 lab grown marquise diamond cost?

As of November 2026, 1.00 to 1.49ct G SI1 lab grown marquise diamonds typically cost £251 GBP to £715 GBP, with a median price of £351 GBP. There are currently 37 diamonds matching this specification available across retailers.

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

About 21% of these diamonds are available at multiple retailers, with an average price spread of 69%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct G SI1 Lab Grown Marquise

Quick answer

As of November 2026, there are 37 lab grown marquise diamonds with G colour and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £251 GBP to £715 GBP, with a median of £351 GBP. At least 28 retailers stock this exact specification, and 21% of the stones appear at more than one of them, with an average price spread of 69%. Half of all listings fall between £222 GBP and £449 GBP per carat. The same specification in natural form lists at a median of about £3,453 GBP per carat. Over the last 30 days the median price moved -2.9% and the number of listings moved +21.3%.

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

Caratlytics Diamond Price Index, October 2026: natural diamonds at 2,202 USD per carat and lab-grown at 462 USD per carat, a natural to lab ratio of 4.8 to 1. Marquise lab grown stones in the index: 505 USD per carat, +1.6% 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

£89 GBP

Highest Price

£1,043 GBP

Average Price

£400 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

21.1%

Price Spread

68.9%

30-Day Price Trend

-2.9%

30-Day Supply Change

+21.3%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$441/ct

10th Percentile

$168

Median

$441

90th Percentile

$814

Score Distribution

71 diamonds scored across 4 quality tiers

Excellent

2 (2.8%)

Very Good

5 (7.0%)

Good

34 (47.9%)

Average

30 (42.3%)

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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