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 $619 NZD to $1,307 NZD, with a median price of $830 NZD. There are currently 15 diamonds matching this specification available across retailers.

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

About 19% of these diamonds are available at multiple retailers, with an average price spread of 36%. 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 15 natural radiant diamonds with I colour and SI1 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run $619 NZD to $1,307 NZD, with a median of $830 NZD. At least 40 retailers stock this exact specification, and 19% of the stones appear at more than one of them, with an average price spread of 36%. Half of all listings fall between $1,882 NZD and $2,707 NZD per carat. Over the last 30 days the median price moved -1.5% and the number of listings moved +3.6%.

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. 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

$409 NZD

Highest Price

$2,301 NZD

Average Price

$912 NZD

Market Intelligence

Retailers Selling

Cross Retailer %

19.1%

Price Spread

36.0%

30-Day Price Trend

-1.5%

30-Day Supply Change

+3.6%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,292/ct

10th Percentile

$930

Median

$1,292

90th Percentile

$1,993

Score Distribution

64 diamonds scored across 4 quality tiers

Excellent

5 (7.8%)

Very Good

4 (6.3%)

Good

10 (15.6%)

Average

45 (70.3%)

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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