How much does a 0.50 to 0.74ct M SI1 natural round diamond cost?

As of November 6, 2026, 0.50 to 0.74ct M SI1 natural round diamonds typically cost £211 GBP to £710 GBP, with a median price of £402 GBP. There are currently 505 diamonds matching this specification available across retailers.

Where can I find the best price on a M SI1 round diamond?

About 47% of these diamonds are available at multiple retailers, with an average price spread of 69%. A comparison tool like Carat Hunter lets you see all the prices side by side.

0.50 to 0.74ct M SI1 Natural Round

Quick answer

As of November 6, 2026, there are 505 natural round diamonds with M colour and SI1 clarity in the 0.50 to 0.74ct range available across retailers worldwide. Prices typically run £211 GBP to £710 GBP, with a median of £402 GBP. Half of all listings fall between £476 GBP and £936 GBP per carat. The same specification in lab grown form lists at a median of about £299 GBP per carat. Over the last 30 days the median price moved -1.0% and the number of listings moved +5.2%.

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

Caratlytics Diamond Price Index, October 2026: natural diamonds at 2,202 USD per carat and lab-grown at 462 USD per carat, a natural to lab ratio of 4.8 to 1. Round natural stones in the index: 2,124 USD per carat, -6.9% month on month. See the full index release

Figures come from current listings across more than 125 retailers. The index is a monthly release.

Last updated: November 6, 2026

Available

505

Lowest Price

£122 GBP

Highest Price

£1,516 GBP

Average Price

£440 GBP

Market Intelligence

Cross Retailer %

47.1%

Price Spread

68.8%

30-Day Price Trend

-1.0%

30-Day Supply Change

+5.2%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$901/ct

10th Percentile

$524

Median

$901

90th Percentile

$1,597

Score Distribution

505 diamonds scored across 4 quality tiers

Excellent

105 (20.8%)

Very Good

123 (24.4%)

Good

131 (25.9%)

Average

146 (28.9%)

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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