How much does a 0.50 to 0.74ct I SI1 natural round diamond cost?

As of October 2026, 0.50 to 0.74ct I SI1 natural round diamonds typically cost $705 AUD to $2,056 AUD, with a median price of $1,114 AUD. There are currently 5,886 diamonds matching this specification available across retailers.

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

About 35% 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.

0.50 to 0.74ct I SI1 Natural Round

Quick answer

As of October 2026, there are 5,886 natural round diamonds with I colour and SI1 clarity in the 0.50 to 0.74ct range available across retailers worldwide. Prices typically run $705 AUD to $2,056 AUD, with a median of $1,114 AUD. At least 66 retailers stock this exact specification, and 35% of the stones appear at more than one of them, with an average price spread of 51%. Half of all listings fall between $1,773 AUD and $2,881 AUD per carat. The same specification in lab grown form lists at a median of about $1,675 AUD per carat. Over the last 30 days the median price moved -2.2% and the number of listings moved +8.0%.

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. Round natural stones in the index: 2,248 USD per carat, +7.6% 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

5,886

Lowest Price

$387 AUD

Highest Price

$4,524 AUD

Average Price

$1,272 AUD