How much does a 5.00ct+ G SI1 natural cushion diamond cost?

As of October 2026, 5.00ct+ G SI1 natural cushion diamonds typically cost £50,093 GBP to £115,142 GBP, with a median price of £76,537 GBP. There are currently 35 diamonds matching this specification available across retailers.

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

About 33% of these diamonds are available at multiple retailers, with an average price spread of 36%. A comparison tool like Carat Hunter lets you see all the prices side by side.

5.00ct+ G SI1 Natural Cushion

Quick answer

As of October 2026, there are 35 natural cushion diamonds with G colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run £50,093 GBP to £115,142 GBP, with a median of £76,537 GBP. At least 41 retailers stock this exact specification, and 33% of the stones appear at more than one of them, with an average price spread of 36%. Half of all listings fall between £12,008 GBP and £17,354 GBP per carat. The same specification in lab grown form lists at a median of about £228 GBP per carat. Over the last 30 days the median price moved +0.2% and the number of listings moved -2.1%.

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: October 2026

Available

Lowest Price

£28,328 GBP

Highest Price

£206,867 GBP

Average Price

£80,409 GBP