How much does a 0.75 to 0.99ct I SI1 natural heart diamond cost?

As of November 2026, 0.75 to 0.99ct I SI1 natural heart diamonds typically cost $1,148 AUD to $3,529 AUD, with a median price of $1,756 AUD. There are currently 172 diamonds matching this specification available across retailers.

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

About 36% of these diamonds are available at multiple retailers, with an average price spread of 90%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI1 Natural Heart

Quick answer

As of November 2026, there are 172 natural heart diamonds with I colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run $1,148 AUD to $3,529 AUD, with a median of $1,756 AUD. At least 60 retailers stock this exact specification, and 36% of the stones appear at more than one of them, with an average price spread of 90%. Half of all listings fall between $1,806 AUD and $3,915 AUD per carat. Over the last 30 days the median price moved -1.5% and the number of listings moved +6.3%.

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. Heart natural stones in the index: 2,374 USD per carat, +9.8% 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

172

Lowest Price

$796 AUD

Highest Price

$8,789 AUD

Average Price

$2,089 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

36.1%

Price Spread

90.0%

30-Day Price Trend

-1.5%

30-Day Supply Change

+6.3%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,647/ct

10th Percentile

$1,077

Median

$1,647

90th Percentile

$3,460

Score Distribution

446 diamonds scored across 4 quality tiers

Excellent

71 (15.9%)

Very Good

70 (15.7%)

Good

140 (31.4%)

Average

165 (37.0%)

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J SI1J 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