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

As of November 2026, 1.50 to 1.99ct H SI1 natural marquise diamonds typically cost £5,553 GBP to £16,248 GBP, with a median price of £8,255 GBP. There are currently 68 diamonds matching this specification available across retailers.

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

About 32% of these diamonds are available at multiple retailers, with an average price spread of 40%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct H SI1 Natural Marquise

Quick answer

As of November 2026, there are 68 natural marquise diamonds with H colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £5,553 GBP to £16,248 GBP, with a median of £8,255 GBP. At least 58 retailers stock this exact specification, and 32% of the stones appear at more than one of them, with an average price spread of 40%. Half of all listings fall between £3,955 GBP and £5,901 GBP per carat. The same specification in lab grown form lists at a median of about £747 GBP per carat. Over the last 30 days the median price moved -4.3% and the number of listings moved +18.3%.

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: November 2026

Available

Lowest Price

£4,021 GBP

Highest Price

£21,125 GBP

Average Price

£9,822 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

32.4%

Price Spread

40.0%

30-Day Price Trend

-4.3%

30-Day Supply Change

+18.3%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$6,525/ct

10th Percentile

$4,429

Median

$6,525

90th Percentile

$9,763

Score Distribution

174 diamonds scored across 4 quality tiers

Excellent

4 (2.3%)

Very Good

30 (17.2%)

Good

53 (30.5%)

Average

87 (50.0%)

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Consider Instead

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

H SI2SI2 inclusions are not visible without magnification

Save 28%

Lab-Grown H SI1Same specifications, lab-grown origin

Save 85%

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