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

As of October 2026, 3.00 to 4.99ct I SI2 lab grown cushion diamonds typically cost $1,749 AUD to $2,393 AUD, with a median price of $2,071 AUD. 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 111%. 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 October 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 $1,749 AUD to $2,393 AUD, with a median of $2,071 AUD. 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 111%. Half of all listings fall between $553 AUD and $1,738 AUD per carat. The same specification in natural form lists at a median of about $15,273 AUD per carat. Over the last 30 days the median price moved +13.7% and the number of listings moved +6.6%.

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: October 2026

Available

Lowest Price

$1,668 AUD

Highest Price

$10,770 AUD

Average Price

$2,071 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

35.3%

Price Spread

110.8%

30-Day Price Trend

+13.7%

30-Day Supply Change

+6.6%

Volatility (30d)

0.05

Price Range

Price per carat distribution across retailers

$753/ct

10th Percentile

$288

Median

$753

90th Percentile

$1,387

Score Distribution

2 diamonds scored across 1 quality tiers

Very Good

2 (100.0%)

Find Your Diamond

Search 2 I SI2 cushion diamonds and compare prices.

Search Diamonds

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