How much does a 3.00 to 4.99ct I SI2 natural cushion diamond cost?

As of September 2026, 3.00 to 4.99ct I SI2 natural cushion diamonds typically cost $18,503 USD to $51,135 USD, with a median price of $29,455 USD. There are currently 185 diamonds matching this specification available across retailers.

Where can I find the best price on a I SI2 cushion diamond?

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3.00 to 4.99ct I SI2 Natural Cushion

Quick answer

As of September 2026, there are 185 natural cushion diamonds with I color and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $18,503 USD to $51,135 USD, with a median of $29,455 USD. At least 45 retailers stock this exact specification. Half of all listings fall between $7,743 USD and $11,327 USD per carat. The same specification in lab grown form lists at a median of about $846 USD per carat.

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

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Cushion natural stones in the index: 2,792 USD per carat, +1.1% month on month. See the full index release

Figures come from live listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: September 2026

Available

185

Lowest Price

$12,459 USD

Highest Price

$123,414 USD

Average Price

$33,335 USD