How much does a 0.75 to 0.99ct G SI1 lab grown cushion diamond cost?

As of October 2026, 0.75 to 0.99ct G SI1 lab grown cushion diamonds typically cost £181 GBP to £1,115 GBP, with a median price of £458 GBP. There are currently 2 diamonds matching this specification available across retailers.

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

About 22% of these diamonds are available at multiple retailers, with an average price spread of 53%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.75 to 0.99ct G SI1 Lab Grown Cushion

Quick answer

As of October 2026, there are 2 lab grown cushion diamonds with G colour and SI1 clarity in the 0.75 to 0.99ct range available across retailers worldwide. Prices typically run £181 GBP to £1,115 GBP, with a median of £458 GBP. At least 22 retailers stock this exact specification, and 22% of the stones appear at more than one of them, with an average price spread of 53%. Half of all listings fall between £348 GBP and £639 GBP per carat. The same specification in natural form lists at a median of about £1,703 GBP per carat. Over the last 30 days the median price moved +25.3% and the number of listings moved -1.7%.

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. Cushion lab grown stones in the index: 516 USD per carat, +6.9% 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

£129 GBP

Highest Price

£1,385 GBP

Average Price

£580 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

22.2%

Price Spread

52.8%

30-Day Price Trend

+25.3%

30-Day Supply Change

-1.7%

Volatility (30d)

0.07

Price Range

Price per carat distribution across retailers

$732/ct

10th Percentile

$344

Median

$732

90th Percentile

$1,078

Score Distribution

8 diamonds scored across 3 quality tiers

Excellent

2 (25.0%)

Very Good

3 (37.5%)

Average

3 (37.5%)

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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