How much does a 5.00ct+ G SI1 natural round diamond cost?

As of October 2026, 5.00ct+ G SI1 natural round diamonds typically cost £70,472 GBP to £150,951 GBP, with a median price of £90,674 GBP. There are currently 62 diamonds matching this specification available across retailers.

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

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5.00ct+ G SI1 Natural Round

Quick answer

As of October 2026, there are 62 natural round diamonds with G colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run £70,472 GBP to £150,951 GBP, with a median of £90,674 GBP. The same specification in lab grown form lists at a median of about £227 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. Round natural stones in the index: 2,248 USD per carat, +7.6% 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

£43,914 GBP

Highest Price

£351,317 GBP

Average Price

£101,609 GBP

Score Distribution

169 diamonds scored across 4 quality tiers

Excellent

19 (11.2%)

Very Good

34 (20.1%)

Good

40 (23.7%)

Average

76 (45.0%)

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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