How much does a 0.75 to 0.99ct I SI1 lab grown radiant diamond cost?

As of October 2026, 0.75 to 0.99ct I SI1 lab grown radiant diamonds typically cost $290 AUD to $1,893 AUD, with a median price of $787 AUD. There are currently 8 diamonds matching this specification available across retailers.

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

About 44% of these diamonds are available at multiple retailers, with an average price spread of 110%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI1 Lab Grown Radiant

Quick answer

As of October 2026, there are 8 lab grown radiant diamonds with I colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run $290 AUD to $1,893 AUD, with a median of $787 AUD. At least 31 retailers stock this exact specification, and 44% of the stones appear at more than one of them, with an average price spread of 110%. Half of all listings fall between $629 AUD and $1,746 AUD per carat. The same specification in natural form lists at a median of about $2,840 AUD per carat. Over the last 30 days the median price moved -1.5% and the number of listings moved +11.7%.

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. Radiant lab grown stones in the index: 474 USD per carat, -2.1% 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

Lowest Price

$145 AUD

Highest Price

$3,788 AUD

Average Price

$965 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

44.0%

Price Spread

109.8%

30-Day Price Trend

-1.5%

30-Day Supply Change

+11.7%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$715/ct

10th Percentile

$240

Median

$715

90th Percentile

$1,959

Score Distribution

15 diamonds scored across 4 quality tiers

Excellent

3 (20.0%)

Very Good

6 (40.0%)

Good

1 (6.7%)

Average

5 (33.3%)

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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