How much does a 1.50 to 1.99ct D SI1 lab grown marquise diamond cost?

As of October 2026, 1.50 to 1.99ct D SI1 lab grown marquise diamonds typically cost £199 GBP to £1,226 GBP, with a median price of £492 GBP. There are currently 26 diamonds matching this specification available across retailers.

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

About 19% of these diamonds are available at multiple retailers, with an average price spread of 92%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct D SI1 Lab Grown Marquise

Quick answer

As of October 2026, there are 26 lab grown marquise diamonds with D colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £199 GBP to £1,226 GBP, with a median of £492 GBP. At least 28 retailers stock this exact specification, and 19% of the stones appear at more than one of them, with an average price spread of 92%. Half of all listings fall between £224 GBP and £512 GBP per carat. The same specification in natural form lists at a median of about £6,241 GBP per carat. Over the last 30 days the median price moved +20.8% and the number of listings moved +26.0%.

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: October 2026

Available

Lowest Price

£156 GBP

Highest Price

£2,024 GBP

Average Price

£562 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

19.1%

Price Spread

91.7%

30-Day Price Trend

+20.8%

30-Day Supply Change

+26.0%

Volatility (30d)

0.09

Price Range

Price per carat distribution across retailers

$417/ct

10th Percentile

$192

Median

$417

90th Percentile

$980

Score Distribution

78 diamonds scored across 4 quality tiers

Excellent

18 (23.1%)

Very Good

4 (5.1%)

Good

10 (12.8%)

Average

46 (59.0%)

Find Your Diamond

Search 26 D SI1 marquise diamonds and compare prices.

Search Diamonds

Consider Instead

Save money without compromising on what matters. These alternatives are visually similar but cost less.

D SI2SI2 inclusions are not visible without magnification

Save 31%

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