How much does a 1.50 to 1.99ct I SI1 natural princess diamond cost?

As of October 2026, 1.50 to 1.99ct I SI1 natural princess diamonds typically cost $3,417 USD to $9,321 USD, with a median price of $6,130 USD. There are currently 211 diamonds matching this specification available across retailers.

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

About 30% of these diamonds are available at multiple retailers, with an average price spread of 59%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct I SI1 Natural Princess

Quick answer

As of October 2026, there are 211 natural princess diamonds with I color and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $3,417 USD to $9,321 USD, with a median of $6,130 USD. At least 59 retailers stock this exact specification, and 30% of the stones appear at more than one of them, with an average price spread of 59%. Half of all listings fall between $2,931 USD and $5,125 USD per carat. The same specification in lab grown form lists at a median of about $886 USD per carat. Over the last 30 days the median price moved -2.5% and the number of listings moved +7.2%.

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. Princess natural stones in the index: 2,158 USD per carat, +5.7% 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

211

Lowest Price

$2,322 USD

Highest Price

$18,473 USD

Average Price

$6,444 USD