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

As of November 2026, 1.00 to 1.49ct H SI1 lab grown marquise diamonds typically cost £351 GBP to £1,247 GBP, with a median price of £720 GBP. There are currently 16 diamonds matching this specification available across retailers.

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

About 38% of these diamonds are available at multiple retailers, with an average price spread of 124%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct H SI1 Lab Grown Marquise

Quick answer

As of November 2026, there are 16 lab grown marquise diamonds with H colour and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £351 GBP to £1,247 GBP, with a median of £720 GBP. At least 18 retailers stock this exact specification, and 38% of the stones appear at more than one of them, with an average price spread of 124%. Half of all listings fall between £477 GBP and £1,372 GBP per carat. The same specification in natural form lists at a median of about £2,982 GBP per carat. Over the last 30 days the median price moved +2.8% and the number of listings moved -0.6%.

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

£283 GBP

Highest Price

£3,771 GBP

Average Price

£801 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

38.2%

Price Spread

124.3%

30-Day Price Trend

+2.8%

30-Day Supply Change

-0.6%

Volatility (30d)

0.02

Price Range

Price per carat distribution across retailers

$966/ct

10th Percentile

$571

Median

$966

90th Percentile

$3,072

Score Distribution

29 diamonds scored across 4 quality tiers

Excellent

8 (27.6%)

Very Good

4 (13.8%)

Good

13 (44.8%)

Average

4 (13.8%)

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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