How much does a 0.20 to 0.49ct G SI1 natural marquise diamond cost?

As of November 2026, 0.20 to 0.49ct G SI1 natural marquise diamonds typically cost £216 GBP to £457 GBP, with a median price of £325 GBP. There are currently 880 diamonds matching this specification available across retailers.

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

About 32% of these diamonds are available at multiple retailers, with an average price spread of 53%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct G SI1 Natural Marquise

Quick answer

As of November 2026, there are 880 natural marquise diamonds with G colour and SI1 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £216 GBP to £457 GBP, with a median of £325 GBP. At least 26 retailers stock this exact specification, and 32% of the stones appear at more than one of them, with an average price spread of 53%. Half of all listings fall between £954 GBP and £1,587 GBP per carat. The same specification in lab grown form lists at a median of about £342 GBP per carat. Over the last 30 days the median price moved -6.1% and the number of listings moved -6.9%.

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. Marquise natural stones in the index: 2,268 USD per carat, +10.8% 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: November 2026

Available

880

Lowest Price

£127 GBP

Highest Price

£995 GBP

Average Price

£341 GBP