How much does a 0.20 to 0.49ct J SI1 natural marquise diamond cost?

As of November 2026, 0.20 to 0.49ct J SI1 natural marquise diamonds typically cost £173 GBP to £470 GBP, with a median price of £267 GBP. There are currently 60 diamonds matching this specification available across retailers.

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

About 26% of these diamonds are available at multiple retailers, with an average price spread of 40%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct J SI1 Natural Marquise

Quick answer

As of November 2026, there are 60 natural marquise diamonds with J colour and SI1 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £173 GBP to £470 GBP, with a median of £267 GBP. At least 34 retailers stock this exact specification, and 26% of the stones appear at more than one of them, with an average price spread of 40%. Half of all listings fall between £648 GBP and £961 GBP per carat. Over the last 30 days the median price moved +0.6% and the number of listings moved +25.8%.

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: November 2026

Available

Lowest Price

£81 GBP

Highest Price

£857 GBP

Average Price

£307 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

26.2%

Price Spread

40.2%

30-Day Price Trend

+0.6%

30-Day Supply Change

+25.8%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,044/ct

10th Percentile

$703

Median

$1,044

90th Percentile

$1,552

Score Distribution

191 diamonds scored across 4 quality tiers

Excellent

17 (8.9%)

Very Good

44 (23.0%)

Good

27 (14.1%)

Average

103 (53.9%)

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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