How much does a 1.50 to 1.99ct I SI1 lab grown radiant diamond cost?

As of October 2026, 1.50 to 1.99ct I SI1 lab grown radiant diamonds typically cost $1,517 AUD to $2,956 AUD, with a median price of $1,843 AUD. There are currently 4 diamonds matching this specification available across retailers.

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

About 20% 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.

1.50 to 1.99ct I SI1 Lab Grown Radiant

Quick answer

As of October 2026, there are 4 lab grown radiant diamonds with I colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $1,517 AUD to $2,956 AUD, with a median of $1,843 AUD. At least 21 retailers stock this exact specification, and 20% of the stones appear at more than one of them, with an average price spread of 90%. Half of all listings fall between $943 AUD and $2,306 AUD per carat. The same specification in natural form lists at a median of about $6,361 AUD per carat. Over the last 30 days the median price moved +1.4% and the number of listings moved +7.1%.

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

$1,261 AUD

Highest Price

$6,904 AUD

Average Price

$2,105 AUD

Market Intelligence

Retailers Selling

Cross Retailer %

20.0%

Price Spread

90.0%

30-Day Price Trend

+1.4%

30-Day Supply Change

+7.1%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,065/ct

10th Percentile

$402

Median

$1,065

90th Percentile

$2,070

Score Distribution

6 diamonds scored across 4 quality tiers

Excellent

2 (33.3%)

Very Good

2 (33.3%)

Good

1 (16.7%)

Average

1 (16.7%)

Find Your Diamond

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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