How much does a 3.00 to 4.99ct I SI2 natural radiant diamond cost?

As of September 2026, 3.00 to 4.99ct I SI2 natural radiant diamonds typically cost $24,471 AUD to $73,295 AUD, with a median price of $43,565 AUD. There are currently 174 diamonds matching this specification available across retailers.

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

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3.00 to 4.99ct I SI2 Natural Radiant

Quick answer

As of September 2026, there are 174 natural radiant diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $24,471 AUD to $73,295 AUD, with a median of $43,565 AUD. At least 35 retailers stock this exact specification. Half of all listings fall between $9,023 AUD and $13,193 AUD per carat. The same specification in lab grown form lists at a median of about $18,453 AUD per carat.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Radiant natural stones in the index: 2,765 USD per carat, +6.0% month on month. See the full index release

Figures come from live listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: September 2026

Available

174

Lowest Price

$13,541 AUD

Highest Price

$189,834 AUD

Average Price

$47,290 AUD

Market Intelligence

Retailers Selling

Price Spread

37.6%

Price Range

Price per carat distribution across retailers

$7,892/ct

10th Percentile

$4,792

Median

$7,892

90th Percentile

$10,316

Score Distribution

174 diamonds scored across 4 quality tiers

Excellent

38 (21.8%)

Very Good

55 (31.6%)

Good

25 (14.4%)

Average

56 (32.2%)

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J SI2J colour is visually identical to I to the naked eye

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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