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

As of October 2026, 0.75 to 0.99ct I SI2 natural cushion diamonds typically cost £502 GBP to £1,834 GBP, with a median price of £888 GBP. There are currently 104 diamonds matching this specification available across retailers.

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

About 28% of these diamonds are available at multiple retailers, with an average price spread of 79%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI2 Natural Cushion

Quick answer

As of October 2026, there are 104 natural cushion diamonds with I colour and SI2 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £502 GBP to £1,834 GBP, with a median of £888 GBP. At least 50 retailers stock this exact specification, and 28% of the stones appear at more than one of them, with an average price spread of 79%. Half of all listings fall between £850 GBP and £1,819 GBP per carat. Over the last 30 days the median price moved +1.4% and the number of listings moved +2.9%.

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. Cushion natural stones in the index: 2,948 USD per carat, +1.7% 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

104

Lowest Price

£323 GBP

Highest Price

£3,899 GBP

Average Price

£1,048 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

28.2%

Price Spread

79.5%

30-Day Price Trend

+1.4%

30-Day Supply Change

+2.9%

Volatility (30d)

0.00

Price Range

Price per carat distribution across retailers

$1,619/ct

10th Percentile

$880

Median

$1,619

90th Percentile

$3,141

Score Distribution

280 diamonds scored across 4 quality tiers

Excellent

31 (11.1%)

Very Good

30 (10.7%)

Good

121 (43.2%)

Average

98 (35.0%)

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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