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

As of October 2026, 1.50 to 1.99ct D SI1 natural marquise diamonds typically cost £7,099 GBP to £18,581 GBP, with a median price of £9,512 GBP. There are currently 128 diamonds matching this specification available across retailers.

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

About 31% of these diamonds are available at multiple retailers, with an average price spread of 33%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct D SI1 Natural Marquise

Quick answer

As of October 2026, there are 128 natural marquise diamonds with D colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £7,099 GBP to £18,581 GBP, with a median of £9,512 GBP. At least 60 retailers stock this exact specification, and 31% of the stones appear at more than one of them, with an average price spread of 33%. Half of all listings fall between £5,367 GBP and £7,431 GBP per carat. The same specification in lab grown form lists at a median of about £314 GBP per carat. Over the last 30 days the median price moved -0.8% and the number of listings moved +15.4%.

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 natural stones in the index: 2,268 USD per carat, +10.8% 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

128

Lowest Price

£5,082 GBP

Highest Price

£24,030 GBP

Average Price

£11,063 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

31.4%

Price Spread

33.1%

30-Day Price Trend

-0.8%

30-Day Supply Change

+15.4%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$8,293/ct

10th Percentile

$6,330

Median

$8,293

90th Percentile

$12,015

Score Distribution

329 diamonds scored across 4 quality tiers

Excellent

43 (13.1%)

Very Good

79 (24.0%)

Good

88 (26.7%)

Average

119 (36.2%)

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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

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Lab-Grown D SI1Same specifications, lab-grown origin

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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