How much does a 3.00 to 4.99ct I SI2 lab grown radiant diamond cost?

As of September 2026, 3.00 to 4.99ct I SI2 lab grown radiant diamonds typically cost $20,876 AUD to $94,531 AUD, with a median price of $75,950 AUD. There are currently 14 diamonds matching this specification available across retailers.

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

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3.00 to 4.99ct I SI2 Lab Grown Radiant

Quick answer

As of September 2026, there are 14 lab grown radiant diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $20,876 AUD to $94,531 AUD, with a median of $75,950 AUD. At least 3 retailers stock this exact specification. Half of all listings fall between $3,457 AUD and $22,658 AUD per carat. The same specification in natural form lists at a median of about $13,911 AUD 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. Radiant lab grown stones in the index: 473 USD per carat, -12.5% 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

$10,589 AUD

Highest Price

$98,628 AUD

Average Price

$67,426 AUD

Market Intelligence

Retailers Selling

Price Spread

105.0%

Price Range

Price per carat distribution across retailers

$11,882/ct

10th Percentile

$2,047

Median

$11,882

90th Percentile

$15,399

Score Distribution

14 diamonds scored across 2 quality tiers

Good

5 (35.7%)

Average

9 (64.3%)

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J SI2J colour is visually identical to I to the naked eye

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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