How much does a 3.00 to 4.99ct I SI1 lab grown radiant diamond cost?

As of October 2026, 3.00 to 4.99ct I SI1 lab grown radiant diamonds typically cost $1,201 NZD to $4,977 NZD, with a median price of $3,174 NZD. There are currently 7 diamonds matching this specification available across retailers.

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

About 38% of these diamonds are available at multiple retailers, with an average price spread of 113%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI1 Lab Grown Radiant

Quick answer

As of October 2026, there are 7 lab grown radiant diamonds with I colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $1,201 NZD to $4,977 NZD, with a median of $3,174 NZD. At least 28 retailers stock this exact specification, and 38% of the stones appear at more than one of them, with an average price spread of 113%. Half of all listings fall between $493 NZD and $1,631 NZD per carat. The same specification in natural form lists at a median of about $24,104 NZD per carat. Over the last 30 days the median price moved +0.8% and the number of listings moved +2.6%.

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. Radiant lab grown stones in the index: 474 USD per carat, -2.1% 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

$1,182 NZD

Highest Price

$14,951 NZD

Average Price

$3,150 NZD

Market Intelligence

Retailers Selling

Cross Retailer %

37.7%

Price Spread

113.4%

30-Day Price Trend

+0.8%

30-Day Supply Change

+2.6%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$563/ct

10th Percentile

$159

Median

$563

90th Percentile

$2,506

Score Distribution

10 diamonds scored across 4 quality tiers

Excellent

2 (20.0%)

Very Good

5 (50.0%)

Good

1 (10.0%)

Average

2 (20.0%)

Find Your Diamond

Search 7 I SI1 radiant 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