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

As of October 2026, 5.00ct+ I SI1 lab grown oval diamonds typically cost $3,831 NZD to $6,979 NZD, with a median price of $5,059 NZD. There are currently 1 diamonds matching this specification available across retailers.

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

About 70% of these diamonds are available at multiple retailers, with an average price spread of 41%. A comparison tool like Carat Hunter lets you see all the prices side by side.

5.00ct+ I SI1 Lab Grown Oval

Quick answer

As of October 2026, there are 1 lab grown oval diamonds with I colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $3,831 NZD to $6,979 NZD, with a median of $5,059 NZD. At least 14 retailers stock this exact specification, and 70% of the stones appear at more than one of them, with an average price spread of 41%. Half of all listings fall between $899 NZD and $1,372 NZD per carat. The same specification in natural form lists at a median of about $34,164 NZD per carat.

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

15.05ct Oval I SI1, IGI, grade A, from $5,059 NZD

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. Oval lab grown stones in the index: 453 USD per carat, -7.4% 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

$3,524 NZD

Highest Price

$20,577 NZD

Average Price

$5,347 NZD

Market Intelligence

Retailers Selling

Cross Retailer %

70.0%

Price Spread

41.1%

Price Range

Price per carat distribution across retailers

$646/ct

10th Percentile

$424

Median

$646

90th Percentile

$1,263

Score Distribution

3 diamonds scored across 3 quality tiers

Excellent

1 (33.3%)

Very Good

1 (33.3%)

Good

1 (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