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

As of November 2026, 0.20 to 0.49ct H SI1 natural marquise diamonds typically cost £207 GBP to £465 GBP, with a median price of £322 GBP. There are currently 403 diamonds matching this specification available across retailers.

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

About 44% of these diamonds are available at multiple retailers, with an average price spread of 30%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.20 to 0.49ct H SI1 Natural Marquise

Quick answer

As of November 2026, there are 403 natural marquise diamonds with H colour and SI1 clarity in the 0.20 to 0.49ct range available across retailers worldwide. Prices typically run £207 GBP to £465 GBP, with a median of £322 GBP. At least 14 retailers stock this exact specification, and 44% of the stones appear at more than one of them, with an average price spread of 30%. Half of all listings fall between £862 GBP and £1,163 GBP per carat. The same specification in lab grown form lists at a median of about £451 GBP per carat. Over the last 30 days the median price moved -7.2% and the number of listings moved -3.7%.

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

403

Lowest Price

£131 GBP

Highest Price

£829 GBP

Average Price

£333 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

43.8%

Price Spread

29.8%

30-Day Price Trend

-7.2%

30-Day Supply Change

-3.7%

Volatility (30d)

0.03

Price Range

Price per carat distribution across retailers

$1,352/ct

10th Percentile

$977

Median

$1,352

90th Percentile

$1,922

Score Distribution

870 diamonds scored across 4 quality tiers

Excellent

46 (5.3%)

Very Good

275 (31.6%)

Good

156 (17.9%)

Average

393 (45.2%)

Find Your Diamond

Search 403 H SI1 marquise diamonds and compare prices.

Search Diamonds

Consider Instead

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

H SI2SI2 inclusions are not visible without magnification

Save 15%

Lab-Grown H SI1Same specifications, lab-grown origin

Save 55%

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