How much does a 0.75 to 0.99ct I SI1 natural cushion diamond cost?

As of November 2026, 0.75 to 0.99ct I SI1 natural cushion diamonds typically cost HK$5,457 HKD to HK$20,313 HKD, with a median price of HK$10,072 HKD. There are currently 187 diamonds matching this specification available across retailers.

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

About 29% of these diamonds are available at multiple retailers, with an average price spread of 76%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI1 Natural Cushion

Quick answer

As of November 2026, there are 187 natural cushion diamonds with I colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run HK$5,457 HKD to HK$20,313 HKD, with a median of HK$10,072 HKD. At least 58 retailers stock this exact specification, and 29% of the stones appear at more than one of them, with an average price spread of 76%. Half of all listings fall between HK$10,029 HKD and HK$21,896 HKD per carat. The same specification in lab grown form lists at a median of about HK$6,433 HKD per carat. Over the last 30 days the median price moved +0.9% and the number of listings moved +2.5%.

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

187

Lowest Price

HK$4,061 HKD

Highest Price

HK$42,048 HKD

Average Price

HK$11,884 HKD