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

As of November 2026, 0.75 to 0.99ct I SI1 natural marquise diamonds typically cost $1,864 NZD to $5,753 NZD, with a median price of $3,552 NZD. There are currently 94 diamonds matching this specification available across retailers.

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

About 23% 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 November 2026, there are 94 natural marquise diamonds with I colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run $1,864 NZD to $5,753 NZD, with a median of $3,552 NZD. At least 59 retailers stock this exact specification, and 23% of the stones appear at more than one of them, with an average price spread of 51%. Half of all listings fall between $3,386 NZD and $5,599 NZD per carat. The same specification in lab grown form lists at a median of about $1,012 NZD per carat. Over the last 30 days the median price moved +0.3% and the number of listings moved +12.3%.

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

Lowest Price

$1,046 NZD

Highest Price

$10,848 NZD

Average Price

$3,729 NZD