How much does a 1.50 to 1.99ct K SI2 natural round diamond cost?

As of November 6, 2026, 1.50 to 1.99ct K SI2 natural round diamonds typically cost $3,129 AUD to $9,772 AUD, with a median price of $5,506 AUD. There are currently 1,506 diamonds matching this specification available across retailers.

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

About 47% of these diamonds are available at multiple retailers, with an average price spread of 57%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct K SI2 Natural Round

Quick answer

As of November 6, 2026, there are 1,506 natural round diamonds with K colour and SI2 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $3,129 AUD to $9,772 AUD, with a median of $5,506 AUD. Half of all listings fall between $2,568 AUD and $4,552 AUD per carat. The same specification in lab grown form lists at a median of about $1,709 AUD per carat. Over the last 30 days the median price moved -0.1% and the number of listings moved +13.2%.

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

Caratlytics Diamond Price Index, October 2026: natural diamonds at 2,202 USD per carat and lab-grown at 462 USD per carat, a natural to lab ratio of 4.8 to 1. Round natural stones in the index: 2,124 USD per carat, -6.9% month on month. See the full index release

Figures come from current listings across more than 125 retailers. The index is a monthly release.

Last updated: November 6, 2026

Available

1,506

Lowest Price

$1,348 AUD

Highest Price

$20,745 AUD

Average Price

$6,011 AUD