How much does a 0.20 to 0.49ct I SI1 natural radiant diamond cost?

As of October 2026, 0.20 to 0.49ct I SI1 natural radiant diamonds typically cost £262 GBP to £499 GBP, with a median price of £343 GBP. There are currently 14 diamonds matching this specification available across retailers.

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

About 18% of these diamonds are available at multiple retailers, with an average price spread of 35%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct I SI1 Natural Radiant

Quick answer

As of October 2026, there are 14 natural radiant diamonds with I colour and SI1 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £262 GBP to £499 GBP, with a median of £343 GBP. At least 40 retailers stock this exact specification, and 18% of the stones appear at more than one of them, with an average price spread of 35%. Half of all listings fall between £805 GBP and £1,150 GBP per carat. Over the last 30 days the median price moved -2.6% and the number of listings moved +6.0%.

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. Radiant natural stones in the index: 3,091 USD per carat, +13.2% 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

£173 GBP

Highest Price

£967 GBP

Average Price

£375 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

18.4%

Price Spread

35.4%

30-Day Price Trend

-2.6%

30-Day Supply Change

+6.0%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,297/ct

10th Percentile

$933

Median

$1,297

90th Percentile

$2,004

Score Distribution

64 diamonds scored across 4 quality tiers

Excellent

5 (7.8%)

Very Good

4 (6.3%)

Good

11 (17.2%)

Average

44 (68.8%)

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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