How much does a 1.50 to 1.99ct K SI1 natural marquise diamond cost?

As of November 7, 2026, 1.50 to 1.99ct K SI1 natural marquise diamonds typically cost $2,875 USD to $6,474 USD, with a median price of $4,481 USD. There are currently 170 diamonds matching this specification available across retailers.

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

About 41% of these diamonds are available at multiple retailers, with an average price spread of 43%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct K SI1 Natural Marquise

Quick answer

As of November 7, 2026, there are 170 natural marquise diamonds with K color and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $2,875 USD to $6,474 USD, with a median of $4,481 USD. Half of all listings fall between $2,285 USD and $3,560 USD per carat. The same specification in lab grown form lists at a median of about $978 USD per carat. Over the last 30 days the median price moved -0.5% and the number of listings moved +19.0%.

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. Marquise natural stones in the index: 2,177 USD per carat, -4.2% month on month. See the full index release

Figures come from current listings across more than 140 retailers. The index is a monthly release.

Last updated: November 7, 2026

Available

170

Lowest Price

$1,893 USD

Highest Price

$14,322 USD

Average Price

$4,697 USD

Market Intelligence

Cross Retailer %

40.6%

Price Spread

43.4%

30-Day Price Trend

-0.5%

30-Day Supply Change

+19.0%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$2,936/ct

10th Percentile

$1,878

Median

$2,936

90th Percentile

$4,246

Score Distribution

170 diamonds scored across 4 quality tiers

Excellent

31 (18.2%)

Very Good

50 (29.4%)

Good

30 (17.6%)

Average

59 (34.7%)

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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