How much does a 1.50 to 1.99ct I SI2 natural radiant diamond cost?

As of October 2026, 1.50 to 1.99ct I SI2 natural radiant diamonds typically cost $3,298 USD to $9,156 USD, with a median price of $5,886 USD. There are currently 183 diamonds matching this specification available across retailers.

Where can I find the best price on a I SI2 radiant diamond?

About 33% of these diamonds are available at multiple retailers, with an average price spread of 48%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct I SI2 Natural Radiant

Quick answer

As of October 2026, there are 183 natural radiant diamonds with I color and SI2 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $3,298 USD to $9,156 USD, with a median of $5,886 USD. At least 55 retailers stock this exact specification, and 33% of the stones appear at more than one of them, with an average price spread of 48%. Half of all listings fall between $2,932 USD and $4,763 USD per carat. The same specification in lab grown form lists at a median of about $932 USD per carat. Over the last 30 days the median price moved -0.7% and the number of listings moved +16.5%.

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. Radiant natural stones in the index: 3,091 USD per carat, +13.2% 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

183

Lowest Price

$2,086 USD

Highest Price

$16,813 USD

Average Price

$6,109 USD

Market Intelligence

Retailers Selling

Cross Retailer %

33.3%

Price Spread

47.9%

30-Day Price Trend

-0.7%

30-Day Supply Change

+16.5%

Volatility (30d)

0.00

Price Range

Price per carat distribution across retailers

$3,825/ct

10th Percentile

$2,334

Median

$3,825

90th Percentile

$5,850

Score Distribution

564 diamonds scored across 4 quality tiers

Excellent

112 (19.9%)

Very Good

105 (18.6%)

Good

123 (21.8%)

Average

224 (39.7%)

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Consider Instead

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

J SI2J colour is visually identical to I to the naked eye

Save 26%

Lab-Grown I SI2Same specifications, lab-grown origin

Save 76%

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