How much does a 0.20 to 0.49ct J SI2 natural marquise diamond cost?

As of October 2026, 0.20 to 0.49ct J SI2 natural marquise diamonds typically cost £165 GBP to £462 GBP, with a median price of £263 GBP. There are currently 32 diamonds matching this specification available across retailers.

Where can I find the best price on a J SI2 marquise diamond?

About 25% of these diamonds are available at multiple retailers, with an average price spread of 43%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct J SI2 Natural Marquise

Quick answer

As of October 2026, there are 32 natural marquise diamonds with J colour and SI2 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £165 GBP to £462 GBP, with a median of £263 GBP. At least 30 retailers stock this exact specification, and 25% of the stones appear at more than one of them, with an average price spread of 43%. Half of all listings fall between £588 GBP and £889 GBP per carat. Over the last 30 days the median price moved +0.3% and the number of listings moved +30.0%.

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. Marquise natural stones in the index: 2,268 USD per carat, +10.8% 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

£112 GBP

Highest Price

£881 GBP

Average Price

£298 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

24.8%

Price Spread

43.2%

30-Day Price Trend

+0.3%

30-Day Supply Change

+30.0%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$934/ct

10th Percentile

$648

Median

$934

90th Percentile

$1,506

Score Distribution

122 diamonds scored across 4 quality tiers

Excellent

3 (2.5%)

Very Good

35 (28.7%)

Good

15 (12.3%)

Average

69 (56.6%)

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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