How much does a 1.00 to 1.49ct F SI1 lab grown cushion diamond cost?

As of October 2026, 1.00 to 1.49ct F SI1 lab grown cushion diamonds typically cost £171 GBP to £634 GBP, with a median price of £386 GBP. There are currently 84 diamonds matching this specification available across retailers.

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

About 24% of these diamonds are available at multiple retailers, with an average price spread of 70%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct F SI1 Lab Grown Cushion

Quick answer

As of October 2026, there are 84 lab grown cushion diamonds with F colour and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £171 GBP to £634 GBP, with a median of £386 GBP. At least 31 retailers stock this exact specification, and 24% of the stones appear at more than one of them, with an average price spread of 70%. Half of all listings fall between £239 GBP and £477 GBP per carat. The same specification in natural form lists at a median of about £2,205 GBP per carat. Over the last 30 days the median price moved +3.5% and the number of listings moved -1.3%.

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

£122 GBP

Highest Price

£1,705 GBP

Average Price

£412 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

23.5%

Price Spread

69.5%

30-Day Price Trend

+3.5%

30-Day Supply Change

-1.3%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$458/ct

10th Percentile

$248

Median

$458

90th Percentile

$949

Score Distribution

216 diamonds scored across 4 quality tiers

Excellent

40 (18.5%)

Very Good

29 (13.4%)

Good

52 (24.1%)

Average

95 (44.0%)

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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