How much does a 0.50 to 0.74ct I SI2 natural marquise diamond cost?

As of November 2026, 0.50 to 0.74ct I SI2 natural marquise diamonds typically cost $677 AUD to $1,701 AUD, with a median price of $1,036 AUD. There are currently 170 diamonds matching this specification available across retailers.

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

About 29% of these diamonds are available at multiple retailers, with an average price spread of 39%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.50 to 0.74ct I SI2 Natural Marquise

Quick answer

As of November 2026, there are 170 natural marquise diamonds with I colour and SI2 clarity in the 0.50 to 0.74ct range available across retailers worldwide. Prices typically run $677 AUD to $1,701 AUD, with a median of $1,036 AUD. At least 53 retailers stock this exact specification, and 29% of the stones appear at more than one of them, with an average price spread of 39%. Half of all listings fall between $1,584 AUD and $2,327 AUD per carat. The same specification in lab grown form lists at a median of about $903 AUD per carat. Over the last 30 days the median price moved -0.9% and the number of listings moved +6.5%.

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

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. Marquise natural stones in the index: 2,268 USD per carat, +10.8% 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

170

Lowest Price

$503 AUD

Highest Price

$3,679 AUD

Average Price

$1,133 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

29.4%

Price Spread

38.9%

30-Day Price Trend

-0.9%

30-Day Supply Change

+6.5%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,343/ct

10th Percentile

$944

Median

$1,343

90th Percentile

$2,149

Score Distribution

430 diamonds scored across 4 quality tiers

Excellent

47 (10.9%)

Very Good

137 (31.9%)

Good

105 (24.4%)

Average

141 (32.8%)

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Consider Instead

Save money without compromising on what matters. These alternatives are visually similar but cost less.

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

Save 9%

Lab-Grown I SI2Same specifications, lab-grown origin

Save 53%

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