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

As of September 2026, 3.00 to 4.99ct I SI1 natural cushion diamonds typically cost HK$172,219 HKD to HK$490,723 HKD, with a median price of HK$279,212 HKD. There are currently 322 diamonds matching this specification available across retailers.

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

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

3.00 to 4.99ct I SI1 Natural Cushion

Quick answer

As of September 2026, there are 322 natural cushion diamonds with I colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run HK$172,219 HKD to HK$490,723 HKD, with a median of HK$279,212 HKD. At least 47 retailers stock this exact specification. Half of all listings fall between HK$73,447 HKD and HK$103,780 HKD per carat. The same specification in lab grown form lists at a median of about HK$4,639 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

322

Lowest Price

HK$74,624 HKD

Highest Price

HK$949,338 HKD

Average Price

HK$307,994 HKD