How much does a 5.00ct+ J SI2 lab grown radiant diamond cost?

As of September 2026, 5.00ct+ J SI2 lab grown radiant diamonds typically cost $88,930 NZD to $139,426 NZD, with a median price of $115,502 NZD. There are currently 6 diamonds matching this specification available across retailers.

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

Compare prices across retailers on Carat Hunter to see all your options.

5.00ct+ J SI2 Lab Grown Radiant

Quick answer

As of September 2026, there are 6 lab grown radiant diamonds with J colour and SI2 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $88,930 NZD to $139,426 NZD, with a median of $115,502 NZD. At least 5 retailers stock this exact specification. Half of all listings fall between $16,764 NZD and $25,773 NZD per carat. The same specification in natural form lists at a median of about $20,509 NZD per carat.

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

$73,702 NZD

Highest Price

$143,563 NZD

Average Price

$114,619 NZD

Market Intelligence

Retailers Selling

Price Spread

41.5%

Price Range

Price per carat distribution across retailers

$13,011/ct

10th Percentile

$4,842

Median

$13,011

90th Percentile

$16,526

Score Distribution

6 diamonds scored across 2 quality tiers

Good

2 (33.3%)

Average

4 (66.7%)

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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