How much does a 1.00 to 1.49ct I SI2 natural cushion diamond cost?

As of October 2026, 1.00 to 1.49ct I SI2 natural cushion diamonds typically cost $1,670 AUD to $4,997 AUD, with a median price of $3,248 AUD. There are currently 367 diamonds matching this specification available across retailers.

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

About 36% of these diamonds are available at multiple retailers, with an average price spread of 59%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct I SI2 Natural Cushion

Quick answer

As of October 2026, there are 367 natural cushion diamonds with I colour and SI2 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run $1,670 AUD to $4,997 AUD, with a median of $3,248 AUD. At least 55 retailers stock this exact specification, and 36% of the stones appear at more than one of them, with an average price spread of 59%. Half of all listings fall between $2,223 AUD and $4,061 AUD per carat. Over the last 30 days the median price moved -1.6% and the number of listings moved +9.9%.

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. Cushion natural stones in the index: 2,948 USD per carat, +1.7% 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: October 2026

Available

367

Lowest Price

$1,081 AUD

Highest Price

$12,406 AUD

Average Price

$3,297 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

36.4%

Price Spread

58.8%

30-Day Price Trend

-1.6%

30-Day Supply Change

+9.9%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$2,194/ct

10th Percentile

$1,216

Median

$2,194

90th Percentile

$3,622

Score Distribution

840 diamonds scored across 4 quality tiers

Excellent

83 (9.9%)

Very Good

181 (21.5%)

Good

251 (29.9%)

Average

325 (38.7%)

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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