How much does a 0.20 to 0.49ct J SI2 natural round diamond cost?

As of October 2026, 0.20 to 0.49ct J SI2 natural round diamonds typically cost £156 GBP to £488 GBP, with a median price of £300 GBP. There are currently 2,269 diamonds matching this specification available across retailers.

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

About 39% of these diamonds are available at multiple retailers, with an average price spread of 55%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct J SI2 Natural Round

Quick answer

As of October 2026, there are 2,269 natural round diamonds with J colour and SI2 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £156 GBP to £488 GBP, with a median of £300 GBP. At least 27 retailers stock this exact specification, and 39% of the stones appear at more than one of them, with an average price spread of 55%. Half of all listings fall between £566 GBP and £952 GBP per carat. The same specification in lab grown form lists at a median of about £343 GBP per carat. Over the last 30 days the median price moved -5.1% 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. Round natural stones in the index: 2,248 USD per carat, +7.6% 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

2,269

Lowest Price

£53 GBP

Highest Price

£1,329 GBP

Average Price

£320 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

38.9%

Price Spread

54.7%

30-Day Price Trend

-5.1%

30-Day Supply Change

+10.6%

Volatility (30d)

0.02

Price Range

Price per carat distribution across retailers

$941/ct

10th Percentile

$620

Median

$941

90th Percentile

$1,715

Score Distribution

4.2K diamonds scored across 4 quality tiers

Excellent

736 (17.4%)

Very Good

1,205 (28.5%)

Good

1,213 (28.7%)

Average

1,073 (25.4%)

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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