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 $105,725 CAD to $251,576 CAD, with a median price of $145,559 CAD. 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 color and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $105,725 CAD to $251,576 CAD, with a median of $145,559 CAD. 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 $34,142 CAD and $44,959 CAD per carat. The same specification in lab grown form lists at a median of about $391 CAD 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

$53,040 CAD

Highest Price

$724,028 CAD

Average Price

$165,953 CAD

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

245 diamonds scored across 4 quality tiers

Excellent

28 (11.4%)

Very Good

55 (22.4%)

Good

63 (25.7%)

Average

99 (40.4%)

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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