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 $6,422 USD to $52,097 USD, with a median price of $10,322 USD. There are currently 6 diamonds matching this specification available across retailers.

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

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5.00ct+ I SI1 Lab Grown Marquise

Quick answer

As of September 2026, there are 6 lab grown marquise diamonds with I color and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $6,422 USD to $52,097 USD, with a median of $10,322 USD. At least 8 retailers stock this exact specification. Half of all listings fall between $331 USD and $703 USD per carat. The same specification in natural form lists at a median of about $24,394 USD 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

$3,049 USD

Highest Price

$96,510 USD

Average Price

$22,947 USD

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

6 diamonds scored across 2 quality tiers

Very Good

1 (16.7%)

Good

5 (83.3%)

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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