How much does a 0.75 to 0.99ct I SI2 natural radiant diamond cost?

As of October 2026, 0.75 to 0.99ct I SI2 natural radiant diamonds typically cost £712 GBP to £1,640 GBP, with a median price of £1,084 GBP. There are currently 47 diamonds matching this specification available across retailers.

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

About 21% of these diamonds are available at multiple retailers, with an average price spread of 55%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI2 Natural Radiant

Quick answer

As of October 2026, there are 47 natural radiant diamonds with I colour and SI2 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £712 GBP to £1,640 GBP, with a median of £1,084 GBP. At least 46 retailers stock this exact specification, and 21% of the stones appear at more than one of them, with an average price spread of 55%. Half of all listings fall between £990 GBP and £1,690 GBP per carat. The same specification in lab grown form lists at a median of about £314 GBP per carat. Over the last 30 days the median price moved +0.9% and the number of listings moved +10.8%.

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. Radiant natural stones in the index: 3,091 USD per carat, +13.2% 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

£442 GBP

Highest Price

£3,864 GBP

Average Price

£1,147 GBP