How much does a 5.00ct+ J SI1 lab grown cushion diamond cost?

As of September 2026, 5.00ct+ J SI1 lab grown cushion diamonds typically cost HK$30,805 HKD to HK$647,051 HKD, with a median price of HK$93,565 HKD. There are currently 10 diamonds matching this specification available across retailers.

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

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

5.00ct+ J SI1 Lab Grown Cushion

Quick answer

As of September 2026, there are 10 lab grown cushion diamonds with J colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run HK$30,805 HKD to HK$647,051 HKD, with a median of HK$93,565 HKD. At least 8 retailers stock this exact specification. Half of all listings fall between HK$5,028 HKD and HK$16,160 HKD per carat. The same specification in natural form lists at a median of about HK$129,201 HKD per carat.

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

5.02ct Cushion J SI1, IGI, score 76 of 100, from HK$20,490 HKD

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

HK$20,490 HKD

Highest Price

HK$695,155 HKD

Average Price

HK$265,077 HKD

Market Intelligence

Retailers Selling

Price Spread

187.2%

Price Range

Price per carat distribution across retailers

$758/ct

10th Percentile

$564

Median

$758

90th Percentile

$2,146

Score Distribution

10 diamonds scored across 3 quality tiers

Very Good

1 (10.0%)

Good

5 (50.0%)

Average

4 (40.0%)

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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