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

As of September 2026, 1.00 to 1.49ct I SI2 natural round diamonds typically cost $2,070 AUD to $5,704 AUD, with a median price of $3,102 AUD. There are currently 5,858 diamonds matching this specification available across retailers.

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

Compare prices across retailers on Carat Hunter to see all your options.

1.00 to 1.49ct I SI2 Natural Round

Quick answer

As of September 2026, there are 5,858 natural round diamonds with I colour and SI2 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run $2,070 AUD to $5,704 AUD, with a median of $3,102 AUD. At least 62 retailers stock this exact specification. Half of all listings fall between $2,696 AUD and $3,874 AUD per carat. The same specification in lab grown form lists at a median of about $2,999 AUD 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. Round natural stones in the index: 2,094 USD per carat, -3.8% 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

5,858

Lowest Price

$883 AUD

Highest Price

$24,273 AUD

Average Price

$3,511 AUD

Market Intelligence

Retailers Selling

Price Spread

36.2%

Price Range

Price per carat distribution across retailers

$2,331/ct

10th Percentile

$1,631

Median

$2,331

90th Percentile

$3,455

Score Distribution

5.9K diamonds scored across 4 quality tiers

Excellent

1,524 (26.0%)

Very Good

1,942 (33.2%)

Good

1,363 (23.3%)

Average

1,029 (17.6%)

Find Your Diamond

Search 5,858 I SI2 round diamonds and compare prices.

Search Diamonds

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 19%

I I1I1 inclusions are not visible without magnification

Save 15%

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