How much does a 0.75 to 0.99ct I SI1 natural marquise diamond cost?

As of October 2026, 0.75 to 0.99ct I SI1 natural marquise diamonds typically cost €950 EUR to €2,936 EUR, with a median price of €1,821 EUR. There are currently 100 diamonds matching this specification available across retailers.

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

About 24% of these diamonds are available at multiple retailers, with an average price spread of 51%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI1 Natural Marquise

Quick answer

As of October 2026, there are 100 natural marquise diamonds with I colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run €950 EUR to €2,936 EUR, with a median of €1,821 EUR. At least 59 retailers stock this exact specification, and 24% of the stones appear at more than one of them, with an average price spread of 51%. Half of all listings fall between €1,714 EUR and €2,831 EUR per carat. The same specification in lab grown form lists at a median of about €512 EUR per carat. Over the last 30 days the median price moved -0.0% and the number of listings moved +12.2%.

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: October 2026

Available

100

Lowest Price

€530 EUR

Highest Price

€5,521 EUR

Average Price

€1,890 EUR