How much does a 0.75 to 0.99ct I SI2 natural marquise diamond cost?

As of October 2026, 0.75 to 0.99ct I SI2 natural marquise diamonds typically cost £694 GBP to £1,981 GBP, with a median price of £1,214 GBP. There are currently 78 diamonds matching this specification available across retailers.

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

About 26% of these diamonds are available at multiple retailers, with an average price spread of 57%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI2 Natural Marquise

Quick answer

As of October 2026, there are 78 natural marquise diamonds with I colour and SI2 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £694 GBP to £1,981 GBP, with a median of £1,214 GBP. At least 48 retailers stock this exact specification, and 26% of the stones appear at more than one of them, with an average price spread of 57%. Half of all listings fall between £1,139 GBP and £1,993 GBP per carat. Over the last 30 days the median price moved +0.4% and the number of listings moved +10.6%.

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

Lowest Price

£430 GBP

Highest Price

£4,056 GBP

Average Price

£1,303 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

25.8%

Price Spread

56.9%

30-Day Price Trend

+0.4%

30-Day Supply Change

+10.6%

Volatility (30d)

0.00

Price Range

Price per carat distribution across retailers

$2,010/ct

10th Percentile

$1,249

Median

$2,010

90th Percentile

$3,400

Score Distribution

238 diamonds scored across 4 quality tiers

Excellent

32 (13.4%)

Very Good

50 (21.0%)

Good

49 (20.6%)

Average

107 (45.0%)

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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