How much does a 5.00ct+ H SI1 lab grown cushion diamond cost?

As of October 2026, 5.00ct+ H SI1 lab grown cushion diamonds typically cost £1,775 GBP to £6,887 GBP, with a median price of £4,607 GBP. There are currently 3 diamonds matching this specification available across retailers.

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

Compare prices across retailers on Carat Hunter to see all your options.

5.00ct+ H SI1 Lab Grown Cushion

Quick answer

As of October 2026, there are 3 lab grown cushion diamonds with H colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run £1,775 GBP to £6,887 GBP, with a median of £4,607 GBP. The same specification in natural form lists at a median of about £12,383 GBP per carat.

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

£939 GBP

Highest Price

£12,515 GBP

Average Price

£4,290 GBP

Score Distribution

10 diamonds scored across 4 quality tiers

Excellent

1 (10.0%)

Very Good

1 (10.0%)

Good

7 (70.0%)

Average

1 (10.0%)

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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