How much does a 1.50 to 1.99ct D SI1 lab grown cushion diamond cost?

As of October 2026, 1.50 to 1.99ct D SI1 lab grown cushion diamonds typically cost £201 GBP to £1,235 GBP, with a median price of £485 GBP. There are currently 186 diamonds matching this specification available across retailers.

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

About 29% of these diamonds are available at multiple retailers, with an average price spread of 97%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct D SI1 Lab Grown Cushion

Quick answer

As of October 2026, there are 186 lab grown cushion diamonds with D colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £201 GBP to £1,235 GBP, with a median of £485 GBP. At least 41 retailers stock this exact specification, and 29% of the stones appear at more than one of them, with an average price spread of 97%. Half of all listings fall between £208 GBP and £518 GBP per carat. The same specification in natural form lists at a median of about £3,805 GBP per carat. Over the last 30 days the median price moved +2.4% and the number of listings moved +13.3%.

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

186

Lowest Price

£157 GBP

Highest Price

£2,331 GBP

Average Price

£609 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

28.8%

Price Spread

96.9%

30-Day Price Trend

+2.4%

30-Day Supply Change

+13.3%

Volatility (30d)

0.03

Price Range

Price per carat distribution across retailers

$427/ct

10th Percentile

$204

Median

$427

90th Percentile

$946

Score Distribution

472 diamonds scored across 4 quality tiers

Excellent

104 (22.0%)

Very Good

88 (18.6%)

Good

66 (14.0%)

Average

214 (45.3%)

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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