How much does a 0.20 to 0.49ct J SI1 natural cushion diamond cost?

As of October 2026, 0.20 to 0.49ct J SI1 natural cushion diamonds typically cost £135 GBP to £390 GBP, with a median price of £248 GBP. There are currently 31 diamonds matching this specification available across retailers.

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

About 50% of these diamonds are available at multiple retailers, with an average price spread of 65%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct J SI1 Natural Cushion

Quick answer

As of October 2026, there are 31 natural cushion diamonds with J colour and SI1 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £135 GBP to £390 GBP, with a median of £248 GBP. At least 9 retailers stock this exact specification, and 50% of the stones appear at more than one of them, with an average price spread of 65%. Half of all listings fall between £625 GBP and £1,106 GBP per carat. Over the last 30 days the median price moved -3.4% and the number of listings moved +25.8%.

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

Lowest Price

£105 GBP

Highest Price

£742 GBP

Average Price

£254 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

50.0%

Price Spread

64.9%

30-Day Price Trend

-3.4%

30-Day Supply Change

+25.8%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$993/ct

10th Percentile

$604

Median

$993

90th Percentile

$1,761

Score Distribution

88 diamonds scored across 4 quality tiers

Excellent

23 (26.1%)

Very Good

8 (9.1%)

Good

22 (25.0%)

Average

35 (39.8%)

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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