How much does a 3.00 to 4.99ct I SI1 natural radiant diamond cost?

As of September 2026, 3.00 to 4.99ct I SI1 natural radiant diamonds typically cost $32,021 AUD to $84,081 AUD, with a median price of $53,478 AUD. There are currently 287 diamonds matching this specification available across retailers.

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

Compare prices across retailers on Carat Hunter to see all your options.

3.00 to 4.99ct I SI1 Natural Radiant

Quick answer

As of September 2026, there are 287 natural radiant diamonds with I colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $32,021 AUD to $84,081 AUD, with a median of $53,478 AUD. At least 41 retailers stock this exact specification. Half of all listings fall between $14,604 AUD and $18,363 AUD per carat. The same specification in lab grown form lists at a median of about $1,047 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

287

Lowest Price

$16,463 AUD

Highest Price

$184,669 AUD

Average Price

$56,593 AUD