How much does a 5.00ct+ I SI1 natural round diamond cost?

As of October 2026, 5.00ct+ I SI1 natural round diamonds typically cost €67,950 EUR to €159,651 EUR, with a median price of €93,090 EUR. There are currently 91 diamonds matching this specification available across retailers.

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

About 47% of these diamonds are available at multiple retailers, with an average price spread of 29%. A comparison tool like Carat Hunter lets you see all the prices side by side.

5.00ct+ I SI1 Natural Round

Quick answer

As of October 2026, there are 91 natural round diamonds with I colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run €67,950 EUR to €159,651 EUR, with a median of €93,090 EUR. At least 28 retailers stock this exact specification, and 47% of the stones appear at more than one of them, with an average price spread of 29%. Half of all listings fall between €21,835 EUR and €28,752 EUR per carat. The same specification in lab grown form lists at a median of about €250 EUR per carat. Over the last 30 days the median price moved +4.3% and the number of listings moved +0.8%.

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. Round natural stones in the index: 2,248 USD per carat, +7.6% 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

€33,895 EUR

Highest Price

€463,040 EUR

Average Price

€105,967 EUR

Market Intelligence

Retailers Selling

Cross Retailer %

46.7%

Price Spread

29.3%

30-Day Price Trend

+4.3%

30-Day Supply Change

+0.8%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$26,400/ct

10th Percentile

$20,810

Median

$26,400

90th Percentile

$40,698

Score Distribution

247 diamonds scored across 4 quality tiers

Excellent

27 (10.9%)

Very Good

56 (22.7%)

Good

65 (26.3%)

Average

99 (40.1%)

Find Your Diamond

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Consider Instead

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

J SI1J colour is visually identical to I to the naked eye

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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