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

As of October 2026, 3.00 to 4.99ct I SI2 lab grown round diamonds typically cost $1,169 NZD to $33,430 NZD, with a median price of $4,950 NZD. There are currently 5 diamonds matching this specification available across retailers.

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

About 43% of these diamonds are available at multiple retailers, with an average price spread of 326%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI2 Lab Grown Round

Quick answer

As of October 2026, there are 5 lab grown round diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $1,169 NZD to $33,430 NZD, with a median of $4,950 NZD. At least 26 retailers stock this exact specification, and 43% of the stones appear at more than one of them, with an average price spread of 326%. Half of all listings fall between $434 NZD and $3,419 NZD per carat. The same specification in natural form lists at a median of about $18,188 NZD per carat. Over the last 30 days the median price moved -44.0% and the number of listings moved -21.8%.

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. Round lab grown stones in the index: 414 USD per carat, -5.0% 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

$1,143 NZD

Highest Price

$44,940 NZD

Average Price

$12,404 NZD

Market Intelligence

Retailers Selling

Cross Retailer %

42.9%

Price Spread

325.7%

30-Day Price Trend

-44.0%

30-Day Supply Change

-21.8%

Volatility (30d)

0.10

Price Range

Price per carat distribution across retailers

$515/ct

10th Percentile

$149

Median

$515

90th Percentile

$3,046

Score Distribution

9 diamonds scored across 4 quality tiers

Excellent

1 (11.1%)

Very Good

3 (33.3%)

Good

2 (22.2%)

Average

3 (33.3%)

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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