How much does a 3.00 to 4.99ct J SI1 natural marquise diamond cost?

As of September 2026, 3.00 to 4.99ct J SI1 natural marquise diamonds typically cost £13,531 GBP to £43,762 GBP, with a median price of £23,889 GBP. There are currently 45 diamonds matching this specification available across retailers.

Where can I find the best price on a J SI1 marquise diamond?

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3.00 to 4.99ct J SI1 Natural Marquise

Quick answer

As of September 2026, there are 45 natural marquise diamonds with J colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £13,531 GBP to £43,762 GBP, with a median of £23,889 GBP. At least 34 retailers stock this exact specification. Half of all listings fall between £4,980 GBP and £8,537 GBP per carat. The same specification in lab grown form lists at a median of about £1,872 GBP per carat.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Marquise natural stones in the index: 2,114 USD per carat, -8.8% month on month. See the full index release

Figures come from live listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: September 2026

Available

Lowest Price

£11,785 GBP

Highest Price

£89,560 GBP

Average Price

£26,379 GBP

Market Intelligence

Retailers Selling

Price Spread

53.0%

Price Range

Price per carat distribution across retailers

$8,961/ct

10th Percentile

$5,412

Median

$8,961

90th Percentile

$12,888

Score Distribution

44 diamonds scored across 4 quality tiers

Excellent

3 (6.8%)

Very Good

11 (25.0%)

Good

16 (36.4%)

Average

14 (31.8%)

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Consider Instead

Save money without compromising on what matters. These alternatives are visually similar but cost less.

J SI2SI2 inclusions are not visible without magnification

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Lab-Grown J SI1Same specifications, lab-grown origin

Save 72%

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