How much does a 3.00 to 4.99ct I SI1 lab grown radiant diamond cost?

As of September 2026, 3.00 to 4.99ct I SI1 lab grown radiant diamonds typically cost $6,124 AUD to $63,710 AUD, with a median price of $9,679 AUD. There are currently 102 diamonds matching this specification available across retailers.

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

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3.00 to 4.99ct I SI1 Lab Grown Radiant

Quick answer

As of September 2026, there are 102 lab grown radiant diamonds with I colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $6,124 AUD to $63,710 AUD, with a median of $9,679 AUD. At least 23 retailers stock this exact specification. Half of all listings fall between $821 AUD and $2,702 AUD per carat. The same specification in natural form lists at a median of about $18,798 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

102

Lowest Price

$798 AUD

Highest Price

$120,338 AUD

Average Price

$18,389 AUD

Market Intelligence

Retailers Selling

Price Spread

144.0%

Price Range

Price per carat distribution across retailers

$849/ct

10th Percentile

$268

Median

$849

90th Percentile

$2,458

Score Distribution

102 diamonds scored across 4 quality tiers

Excellent

3 (2.9%)

Very Good

9 (8.8%)

Good

75 (73.5%)

Average

15 (14.7%)

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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