How much does a 5.00ct+ I SI2 natural cushion diamond cost?

As of September 2026, 5.00ct+ I SI2 natural cushion diamonds typically cost HK$373,129 HKD to HK$1,403,067 HKD, with a median price of HK$568,419 HKD. There are currently 85 diamonds matching this specification available across retailers.

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

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

5.00ct+ I SI2 Natural Cushion

Quick answer

As of September 2026, there are 85 natural cushion diamonds with I colour and SI2 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run HK$373,129 HKD to HK$1,403,067 HKD, with a median of HK$568,419 HKD. At least 8 retailers stock this exact specification. Half of all listings fall between HK$176,323 HKD and HK$263,162 HKD per carat. The same specification in lab grown form lists at a median of about HK$21,126 HKD 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. Cushion natural stones in the index: 2,792 USD per carat, +1.1% 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

Lowest Price

HK$166,292 HKD

Highest Price

HK$3,378,025 HKD

Average Price

HK$771,790 HKD