How much does a 1.00 to 1.49ct I SI1 natural marquise diamond cost?

As of November 2026, 1.00 to 1.49ct I SI1 natural marquise diamonds typically cost $1,946 USD to $5,599 USD, with a median price of $3,121 USD. There are currently 251 diamonds matching this specification available across retailers.

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

About 39% of these diamonds are available at multiple retailers, with an average price spread of 46%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct I SI1 Natural Marquise

Quick answer

As of November 2026, there are 251 natural marquise diamonds with I color and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run $1,946 USD to $5,599 USD, with a median of $3,121 USD. At least 62 retailers stock this exact specification, and 39% of the stones appear at more than one of them, with an average price spread of 46%. Half of all listings fall between $2,721 USD and $4,259 USD per carat. The same specification in lab grown form lists at a median of about $845 USD per carat. Over the last 30 days the median price moved +0.5% and the number of listings moved +16.8%.

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

Caratlytics Diamond Price Index, October 2026: natural diamonds at 2,202 USD per carat and lab-grown at 462 USD per carat, a natural to lab ratio of 4.8 to 1. Marquise natural stones in the index: 2,177 USD per carat, -4.2% 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

251

Lowest Price

$1,350 USD

Highest Price

$12,198 USD

Average Price

$3,616 USD