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

As of September 2026, 5.00ct+ I SI1 lab grown marquise diamonds typically cost $10,882 AUD to $67,441 AUD, with a median price of $15,289 AUD. There are currently 7 diamonds matching this specification available across retailers.

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

Compare prices across retailers on Carat Hunter to see all your options.

5.00ct+ I SI1 Lab Grown Marquise

Quick answer

As of September 2026, there are 7 lab grown marquise diamonds with I colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $10,882 AUD to $67,441 AUD, with a median of $15,289 AUD. At least 8 retailers stock this exact specification. Half of all listings fall between $508 AUD and $1,081 AUD per carat. The same specification in natural form lists at a median of about $37,530 AUD 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. Marquise lab grown stones in the index: 500 USD per carat, -14.7% 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

$4,691 AUD

Highest Price

$148,477 AUD

Average Price

$32,398 AUD

Market Intelligence

Retailers Selling

Price Spread

71.8%

Price Range

Price per carat distribution across retailers

$518/ct

10th Percentile

$210

Median

$518

90th Percentile

$1,898

Score Distribution

7 diamonds scored across 2 quality tiers

Very Good

1 (14.3%)

Good

6 (85.7%)

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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