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

As of October 2026, 1.00 to 1.49ct I SI1 natural radiant diamonds typically cost $1,521 USD to $4,774 USD, with a median price of $2,594 USD. There are currently 242 diamonds matching this specification available across retailers.

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

About 36% of these diamonds are available at multiple retailers, with an average price spread of 56%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct I SI1 Natural Radiant

Quick answer

As of October 2026, there are 242 natural radiant diamonds with I color and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run $1,521 USD to $4,774 USD, with a median of $2,594 USD. At least 64 retailers stock this exact specification, and 36% of the stones appear at more than one of them, with an average price spread of 56%. Half of all listings fall between $1,904 USD and $3,237 USD per carat. The same specification in lab grown form lists at a median of about $750 USD per carat. Over the last 30 days the median price moved -0.2% and the number of listings moved +14.0%.

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. Radiant natural stones in the index: 3,091 USD per carat, +13.2% 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: October 2026

Available

242

Lowest Price

$922 USD

Highest Price

$8,535 USD

Average Price

$2,852 USD