How much does a 5.00ct+ I SI1 lab grown round diamond cost?

As of September 2026, 5.00ct+ I SI1 lab grown round diamonds typically cost $16,095 NZD to $305,045 NZD, with a median price of $59,650 NZD. There are currently 14 diamonds matching this specification available across retailers.

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

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5.00ct+ I SI1 Lab Grown Round

Quick answer

As of September 2026, there are 14 lab grown round diamonds with I colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $16,095 NZD to $305,045 NZD, with a median of $59,650 NZD. At least 7 retailers stock this exact specification. Half of all listings fall between $2,397 NZD and $4,297 NZD per carat. The same specification in natural form lists at a median of about $30,112 NZD 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. Round lab grown stones in the index: 438 USD per carat, -14.1% 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

$2,446 NZD

Highest Price

$713,579 NZD

Average Price

$149,387 NZD

Market Intelligence

Retailers Selling

Price Spread

63.8%

Price Range

Price per carat distribution across retailers

$1,715/ct

10th Percentile

$1,222

Median

$1,715

90th Percentile

$2,861

Score Distribution

14 diamonds scored across 3 quality tiers

Very Good

7 (50.0%)

Good

2 (14.3%)

Average

5 (35.7%)

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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