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

As of September 2026, 5.00ct+ I SI1 natural round diamonds typically cost $96,839 NZD to $290,718 NZD, with a median price of $161,592 NZD. There are currently 319 diamonds matching this specification available across retailers.

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

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5.00ct+ I SI1 Natural Round

Quick answer

As of September 2026, there are 319 natural round diamonds with I colour and SI1 clarity in the 5.00ct+ range available across retailers worldwide. Prices typically run $96,839 NZD to $290,718 NZD, with a median of $161,592 NZD. At least 5 retailers stock this exact specification. Half of all listings fall between $21,452 NZD and $33,207 NZD per carat. The same specification in lab grown form lists at a median of about $1,961 NZD per carat.

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

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Round natural stones in the index: 2,094 USD per carat, -3.8% month on month. See the full index release

Figures come from live listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: September 2026

Available

319

Lowest Price

$44,130 NZD

Highest Price

$906,556 NZD

Average Price

$190,526 NZD

Market Intelligence

Retailers Selling

Price Spread

40.1%

Price Range

Price per carat distribution across retailers

$16,887/ct

10th Percentile

$11,259

Median

$16,887

90th Percentile

$20,569

Score Distribution

319 diamonds scored across 4 quality tiers

Excellent

55 (17.2%)

Very Good

75 (23.5%)

Good

108 (33.9%)

Average

81 (25.4%)

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Consider Instead

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

Lab-Grown I SI1Same specifications, lab-grown origin

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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