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

As of October 2026, 0.75 to 0.99ct I SI2 natural heart diamonds typically cost £594 GBP to £1,830 GBP, with a median price of £852 GBP. There are currently 95 diamonds matching this specification available across retailers.

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

About 32% of these diamonds are available at multiple retailers, with an average price spread of 88%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI2 Natural Heart

Quick answer

As of October 2026, there are 95 natural heart diamonds with I colour and SI2 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £594 GBP to £1,830 GBP, with a median of £852 GBP. At least 52 retailers stock this exact specification, and 32% of the stones appear at more than one of them, with an average price spread of 88%. Half of all listings fall between £858 GBP and £1,862 GBP per carat. The same specification in lab grown form lists at a median of about £682 GBP per carat. Over the last 30 days the median price moved -2.4% and the number of listings moved +10.6%.

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. Heart natural stones in the index: 2,374 USD per carat, +9.8% 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

£388 GBP

Highest Price

£4,350 GBP

Average Price

£1,059 GBP