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

As of October 2026, 0.75 to 0.99ct I SI1 lab grown round diamonds typically cost $473 USD to $1,462 USD, with a median price of $695 USD. There are currently 8 diamonds matching this specification available across retailers.

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

About 15% of these diamonds are available at multiple retailers, with an average price spread of 152%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct I SI1 Lab Grown Round

Quick answer

As of October 2026, there are 8 lab grown round diamonds with I color and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run $473 USD to $1,462 USD, with a median of $695 USD. At least 25 retailers stock this exact specification, and 15% of the stones appear at more than one of them, with an average price spread of 152%. Half of all listings fall between $763 USD and $2,824 USD per carat. The same specification in natural form lists at a median of about $2,110 USD per carat. Over the last 30 days the median price moved -34.7% and the number of listings moved -45.0%.

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. Round lab grown stones in the index: 414 USD per carat, -5.0% 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

$344 USD

Highest Price

$3,818 USD

Average Price

$823 USD

Market Intelligence

Retailers Selling

Cross Retailer %

15.5%

Price Spread

152.5%

30-Day Price Trend

-34.7%

30-Day Supply Change

-45.0%

Volatility (30d)

0.16

Price Range

Price per carat distribution across retailers

$1,352/ct

10th Percentile

$334

Median

$1,352

90th Percentile

$4,685

Score Distribution

15 diamonds scored across 4 quality tiers

Excellent

5 (33.3%)

Very Good

6 (40.0%)

Good

3 (20.0%)

Average

1 (6.7%)

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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