How much does a 0.50 to 0.74ct H SI1 natural marquise diamond cost?

As of October 2026, 0.50 to 0.74ct H SI1 natural marquise diamonds typically cost £421 GBP to £1,155 GBP, with a median price of £625 GBP. There are currently 382 diamonds matching this specification available across retailers.

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

About 32% of these diamonds are available at multiple retailers, with an average price spread of 41%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.50 to 0.74ct H SI1 Natural Marquise

Quick answer

As of October 2026, there are 382 natural marquise diamonds with H colour and SI1 clarity in the 0.50 to 0.74ct range available across retailers worldwide. Prices typically run £421 GBP to £1,155 GBP, with a median of £625 GBP. At least 61 retailers stock this exact specification, and 32% of the stones appear at more than one of them, with an average price spread of 41%. Half of all listings fall between £933 GBP and £1,397 GBP per carat. The same specification in lab grown form lists at a median of about £563 GBP per carat. Over the last 30 days the median price moved -1.6% and the number of listings moved +7.2%.

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

382

Lowest Price

£275 GBP

Highest Price

£2,037 GBP

Average Price

£718 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

31.7%

Price Spread

41.1%

30-Day Price Trend

-1.6%

30-Day Supply Change

+7.2%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,500/ct

10th Percentile

$1,051

Median

$1,500

90th Percentile

$2,422

Score Distribution

993 diamonds scored across 4 quality tiers

Excellent

93 (9.4%)

Very Good

303 (30.5%)

Good

266 (26.8%)

Average

331 (33.3%)

Find Your Diamond

Search 382 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 10%

Lab-Grown H SI1Same specifications, lab-grown origin

Save 50%

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