How much does a 3.00 to 4.99ct K SI1 natural round diamond cost?

As of November 6, 2026, 3.00 to 4.99ct K SI1 natural round diamonds typically cost $24,675 AUD to $62,793 AUD, with a median price of $36,428 AUD. There are currently 657 diamonds matching this specification available across retailers.

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

About 41% of these diamonds are available at multiple retailers, with an average price spread of 44%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct K SI1 Natural Round

Quick answer

As of November 6, 2026, there are 657 natural round diamonds with K colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $24,675 AUD to $62,793 AUD, with a median of $36,428 AUD. Half of all listings fall between $9,179 AUD and $14,074 AUD per carat. The same specification in lab grown form lists at a median of about $2,187 AUD per carat. Over the last 30 days the median price moved -1.5% and the number of listings moved +12.5%.

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

Caratlytics Diamond Price Index, October 2026: natural diamonds at 2,202 USD per carat and lab-grown at 462 USD per carat, a natural to lab ratio of 4.8 to 1. Round natural stones in the index: 2,124 USD per carat, -6.9% month on month. See the full index release

Figures come from current listings across more than 125 retailers. The index is a monthly release.

Last updated: November 6, 2026

Available

657

Lowest Price

$14,078 AUD

Highest Price

$121,348 AUD

Average Price

$41,354 AUD