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 $4,869 AUD to $13,258 AUD, with a median price of $8,616 AUD. There are currently 188 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 58%. 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 188 natural princess diamonds with I colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $4,869 AUD to $13,258 AUD, with a median of $8,616 AUD. 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 58%. Half of all listings fall between $4,181 AUD and $7,256 AUD per carat. The same specification in lab grown form lists at a median of about $1,227 AUD per carat. Over the last 30 days the median price moved -3.5% and the number of listings moved +8.7%.

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

188

Lowest Price

$3,296 AUD

Highest Price

$26,298 AUD

Average Price

$9,138 AUD