How much does a 1.50 to 1.99ct H SI2 lab grown marquise diamond cost?

As of October 2026, 1.50 to 1.99ct H SI2 lab grown marquise diamonds typically cost £780 GBP to £1,470 GBP, with a median price of £1,125 GBP. There are currently 1 diamonds matching this specification available across retailers.

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

About 25% of these diamonds are available at multiple retailers, with an average price spread of 67%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct H SI2 Lab Grown Marquise

Quick answer

As of October 2026, there are 1 lab grown marquise diamonds with H colour and SI2 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £780 GBP to £1,470 GBP, with a median of £1,125 GBP. At least 13 retailers stock this exact specification, and 25% of the stones appear at more than one of them, with an average price spread of 67%. Half of all listings fall between £643 GBP and £1,332 GBP per carat. The same specification in natural form lists at a median of about £3,503 GBP per carat. Over the last 30 days the median price moved -8.3% and the number of listings moved -14.7%.

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

1.50ct Marquise H SI2, IGI, grade A, from £694 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

£694 GBP

Highest Price

£3,371 GBP

Average Price

£1,125 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

25.0%

Price Spread

67.3%

30-Day Price Trend

-8.3%

30-Day Supply Change

-14.7%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,371/ct

10th Percentile

$767

Median

$1,371

90th Percentile

$3,017

Score Distribution

2 diamonds scored across 2 quality tiers

Excellent

1 (50.0%)

Average

1 (50.0%)

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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