How much does a 3.00 to 4.99ct I SI2 natural marquise diamond cost?

As of November 2026, 3.00 to 4.99ct I SI2 natural marquise diamonds typically cost $24,081 AUD to $88,184 AUD, with a median price of $47,474 AUD. There are currently 45 diamonds matching this specification available across retailers.

Where can I find the best price on a I SI2 marquise diamond?

About 47% of these diamonds are available at multiple retailers, with an average price spread of 54%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI2 Natural Marquise

Quick answer

As of November 2026, there are 45 natural marquise diamonds with I colour and SI2 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run $24,081 AUD to $88,184 AUD, with a median of $47,474 AUD. At least 48 retailers stock this exact specification, and 47% of the stones appear at more than one of them, with an average price spread of 54%. Half of all listings fall between $9,919 AUD and $17,771 AUD per carat. Over the last 30 days the median price moved -3.6% and the number of listings moved +31.7%.

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

Caratlytics Diamond Price Index, October 2026: natural diamonds at 2,202 USD per carat and lab-grown at 462 USD per carat, a natural to lab ratio of 4.8 to 1. Marquise natural stones in the index: 2,177 USD per carat, -4.2% 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: November 2026

Available

Lowest Price

$17,015 AUD

Highest Price

$109,688 AUD

Average Price

$50,797 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

46.6%

Price Spread

54.4%

30-Day Price Trend

-3.6%

30-Day Supply Change

+31.7%

Volatility (30d)

0.02

Price Range

Price per carat distribution across retailers

$10,131/ct

10th Percentile

$5,651

Median

$10,131

90th Percentile

$13,784

Score Distribution

95 diamonds scored across 4 quality tiers

Excellent

21 (22.1%)

Very Good

29 (30.5%)

Good

19 (20.0%)

Average

26 (27.4%)

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J SI2J colour is visually identical to I to the naked eye

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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