How much does a 1.00 to 1.49ct I SI2 natural cushion diamond cost?

As of September 2026, 1.00 to 1.49ct I SI2 natural cushion diamonds typically cost £845 GBP to £2,619 GBP, with a median price of £1,502 GBP. There are currently 761 diamonds matching this specification available across retailers.

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

Compare prices across retailers on Carat Hunter to see all your options.

1.00 to 1.49ct I SI2 Natural Cushion

Quick answer

As of September 2026, there are 761 natural cushion diamonds with I colour and SI2 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £845 GBP to £2,619 GBP, with a median of £1,502 GBP. At least 48 retailers stock this exact specification. Half of all listings fall between £1,160 GBP and £2,087 GBP per carat. The same specification in lab grown form lists at a median of about £894 GBP per carat.

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

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Cushion natural stones in the index: 2,792 USD per carat, +1.1% month on month. See the full index release

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

Last updated: September 2026

Available

761

Lowest Price

£523 GBP

Highest Price

£5,750 GBP

Average Price

£1,643 GBP