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

As of November 2026, 3.00 to 4.99ct I SI1 natural cushion diamonds typically cost HK$165,346 HKD to HK$536,869 HKD, with a median price of HK$284,501 HKD. There are currently 167 diamonds matching this specification available across retailers.

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

About 43% of these diamonds are available at multiple retailers, with an average price spread of 33%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI1 Natural Cushion

Quick answer

As of November 2026, there are 167 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$165,346 HKD to HK$536,869 HKD, with a median of HK$284,501 HKD. At least 56 retailers stock this exact specification, and 43% of the stones appear at more than one of them, with an average price spread of 33%. Half of all listings fall between HK$74,230 HKD and HK$104,072 HKD per carat. The same specification in lab grown form lists at a median of about HK$3,707 HKD per carat. Over the last 30 days the median price moved -0.7% and the number of listings moved +13.4%.

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

Caratlytics Diamond Price Index, September 2026: natural diamonds at 2,335 USD per carat and lab-grown at 443 USD per carat, a natural to lab ratio of 5.3 to 1. Cushion natural stones in the index: 2,948 USD per carat, +1.7% month on month. See the full index release

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

Last updated: November 2026

Available

167

Lowest Price

HK$90,409 HKD

Highest Price

HK$968,269 HKD

Average Price

HK$328,640 HKD