How much does a 3.00 to 4.99ct J SI1 lab grown cushion diamond cost?

As of September 2026, 3.00 to 4.99ct J SI1 lab grown cushion diamonds typically cost HK$43,554 HKD to HK$66,718 HKD, with a median price of HK$49,601 HKD. There are currently 85 diamonds matching this specification available across retailers.

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

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3.00 to 4.99ct J SI1 Lab Grown Cushion

Quick answer

As of September 2026, there are 85 lab grown cushion diamonds with J colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run HK$43,554 HKD to HK$66,718 HKD, with a median of HK$49,601 HKD. At least 10 retailers stock this exact specification. Half of all listings fall between HK$14,370 HKD and HK$15,500 HKD per carat. The same specification in natural form lists at a median of about HK$66,795 HKD 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

HK$20,311 HKD

Highest Price

HK$282,328 HKD

Average Price

HK$65,432 HKD

Market Intelligence

Retailers Selling

Price Spread

7.4%

Price Range

Price per carat distribution across retailers

$1,955/ct

10th Percentile

$1,830

Median

$1,955

90th Percentile

$8,205

Score Distribution

85 diamonds scored across 3 quality tiers

Very Good

4 (4.7%)

Good

76 (89.4%)

Average

5 (5.9%)

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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