How much does a 5.00ct+ I SI2 lab grown round diamond cost?

As of September 2026, 5.00ct+ I SI2 lab grown round diamonds typically cost $41,964 AUD to $178,656 AUD, with a median price of $103,789 AUD. There are currently 19 diamonds matching this specification available across retailers.

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

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5.00ct+ I SI2 Lab Grown Round

Quick answer

As of September 2026, there are 19 lab grown round diamonds with I colour and SI2 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $41,964 AUD to $178,656 AUD, with a median of $103,789 AUD. At least 6 retailers stock this exact specification. Half of all listings fall between $9,834 AUD and $22,657 AUD per carat. The same specification in natural form lists at a median of about $24,580 AUD per carat.

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

5.01ct Round I SI2, GIA, score 63 of 100, from $120,646 AUD

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. Round lab grown stones in the index: 438 USD per carat, -14.1% 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

Lowest Price

$32,340 AUD

Highest Price

$243,785 AUD

Average Price

$108,468 AUD

Market Intelligence

Retailers Selling

Price Spread

77.1%

Price Range

Price per carat distribution across retailers

$10,813/ct

10th Percentile

$5,369

Median

$10,813

90th Percentile

$24,287

Score Distribution

19 diamonds scored across 2 quality tiers

Good

10 (52.6%)

Average

9 (47.4%)

Find Your Diamond

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Related Specifications

D IF D VVS1 D VVS2 D VS1 D VS2 D SI1 E IF E VVS1 E VVS2 E VS1 E VS2 E SI1 F IF F VVS1 F VVS2 F VS1 F VS2 F SI1 G IF G VVS1 G VVS2 G VS1 G VS2 G SI1 H IF H VVS1 H VVS2 H VS1 H VS2 H SI1 I IF I VVS1 I VVS2 I VS1 I VS2 I SI1