How much does a 3.00 to 4.99ct J SI2 lab grown cushion diamond cost?

As of September 2026, 3.00 to 4.99ct J SI2 lab grown cushion diamonds typically cost $11,872 AUD to $76,929 AUD, with a median price of $37,066 AUD. There are currently 20 diamonds matching this specification available across retailers.

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

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3.00 to 4.99ct J SI2 Lab Grown Cushion

Quick answer

As of September 2026, there are 20 lab grown cushion diamonds with J colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $11,872 AUD to $76,929 AUD, with a median of $37,066 AUD. At least 5 retailers stock this exact specification. Half of all listings fall between $3,799 AUD and $7,055 AUD per carat. The same specification in natural form lists at a median of about $12,215 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. Cushion lab grown stones in the index: 466 USD per carat, -14.7% 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

$3,430 AUD

Highest Price

$82,491 AUD

Average Price

$36,745 AUD

Market Intelligence

Retailers Selling

Price Spread

80.5%

Price Range

Price per carat distribution across retailers

$2,900/ct

10th Percentile

$1,173

Median

$2,900

90th Percentile

$9,441

Score Distribution

20 diamonds scored across 3 quality tiers

Very Good

2 (10.0%)

Good

1 (5.0%)

Average

17 (85.0%)

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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