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

As of November 2026, 3.00 to 4.99ct I SI2 lab grown cushion diamonds typically cost HK$9,648 HKD to HK$13,207 HKD, with a median price of HK$11,427 HKD. There are currently 2 diamonds matching this specification available across retailers.

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

About 35% of these diamonds are available at multiple retailers, with an average price spread of 124%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI2 Lab Grown Cushion

Quick answer

As of November 2026, there are 2 lab grown cushion diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run HK$9,648 HKD to HK$13,207 HKD, with a median of HK$11,427 HKD. At least 16 retailers stock this exact specification, and 35% of the stones appear at more than one of them, with an average price spread of 124%. Half of all listings fall between HK$3,049 HKD and HK$9,590 HKD per carat. The same specification in natural form lists at a median of about HK$84,954 HKD per carat. Over the last 30 days the median price moved +6.8% and the number of listings moved +2.8%.

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

Caratlytics Diamond Price Index, September 2026: natural diamonds at 2,335 USD per carat and lab-grown at 443 USD per carat, a natural to lab ratio of 5.3 to 1. Cushion lab grown stones in the index: 516 USD per carat, +6.9% month on month. See the full index release

Figures come from current listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: November 2026

Available

Lowest Price

HK$9,203 HKD

Highest Price

HK$59,655 HKD

Average Price

HK$11,427 HKD

Market Intelligence

Retailers Selling

Cross Retailer %

35.3%

Price Spread

123.8%

30-Day Price Trend

+6.8%

30-Day Supply Change

+2.8%

Volatility (30d)

0.05

Price Range

Price per carat distribution across retailers

$674/ct

10th Percentile

$288

Median

$674

90th Percentile

$1,387

Score Distribution

2 diamonds scored across 1 quality tiers

Very Good

2 (100.0%)

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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