How much does a 0.50 to 0.74ct I SI1 natural cushion diamond cost?

As of October 2026, 0.50 to 0.74ct I SI1 natural cushion diamonds typically cost £305 GBP to £993 GBP, with a median price of £448 GBP. There are currently 105 diamonds matching this specification available across retailers.

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

About 25% of these diamonds are available at multiple retailers, with an average price spread of 67%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.50 to 0.74ct I SI1 Natural Cushion

Quick answer

As of October 2026, there are 105 natural cushion diamonds with I colour and SI1 clarity in the 0.50 to 0.74ct range available across retailers worldwide. Prices typically run £305 GBP to £993 GBP, with a median of £448 GBP. At least 49 retailers stock this exact specification, and 25% of the stones appear at more than one of them, with an average price spread of 67%. Half of all listings fall between £646 GBP and £1,212 GBP per carat. Over the last 30 days the median price moved +3.4% and the number of listings moved -1.8%.

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

105

Lowest Price

£213 GBP

Highest Price

£2,120 GBP

Average Price

£560 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

24.6%

Price Spread

66.8%

30-Day Price Trend

+3.4%

30-Day Supply Change

-1.8%

Volatility (30d)

0.02

Price Range

Price per carat distribution across retailers

$1,127/ct

10th Percentile

$719

Median

$1,127

90th Percentile

$2,145

Score Distribution

316 diamonds scored across 4 quality tiers

Excellent

45 (14.2%)

Very Good

61 (19.3%)

Good

120 (38.0%)

Average

90 (28.5%)

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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