How much does a 1.50 to 1.99ct G SI1 natural cushion diamond cost?

As of October 2026, 1.50 to 1.99ct G SI1 natural cushion diamonds typically cost £2,888 GBP to £8,334 GBP, with a median price of £5,241 GBP. There are currently 374 diamonds matching this specification available across retailers.

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

About 31% of these diamonds are available at multiple retailers, with an average price spread of 57%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct G SI1 Natural Cushion

Quick answer

As of October 2026, there are 374 natural cushion diamonds with G colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £2,888 GBP to £8,334 GBP, with a median of £5,241 GBP. At least 60 retailers stock this exact specification, and 31% of the stones appear at more than one of them, with an average price spread of 57%. Half of all listings fall between £2,616 GBP and £4,644 GBP per carat. The same specification in lab grown form lists at a median of about £352 GBP per carat. Over the last 30 days the median price moved -2.6% and the number of listings moved +5.3%.

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

374

Lowest Price

£1,683 GBP

Highest Price

£16,674 GBP

Average Price

£5,499 GBP