How much does a 1.50 to 1.99ct M SI2 natural round diamond cost?

As of November 6, 2026, 1.50 to 1.99ct M SI2 natural round diamonds typically cost $2,072 AUD to $6,795 AUD, with a median price of $3,983 AUD. There are currently 415 diamonds matching this specification available across retailers.

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

About 58% of these diamonds are available at multiple retailers, with an average price spread of 52%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct M SI2 Natural Round

Quick answer

As of November 6, 2026, there are 415 natural round diamonds with M colour and SI2 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run $2,072 AUD to $6,795 AUD, with a median of $3,983 AUD. Half of all listings fall between $1,962 AUD and $3,290 AUD per carat. The same specification in lab grown form lists at a median of about $970 AUD per carat. Over the last 30 days the median price moved +3.9% and the number of listings moved +21.0%.

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. Round natural stones in the index: 2,124 USD per carat, -6.9% month on month. See the full index release

Figures come from current listings across more than 125 retailers. The index is a monthly release.

Last updated: November 6, 2026

Available

415

Lowest Price

$936 AUD

Highest Price

$14,309 AUD

Average Price

$4,202 AUD

Market Intelligence

Cross Retailer %

57.8%

Price Spread

52.5%

30-Day Price Trend

+3.9%

30-Day Supply Change

+21.0%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$1,772/ct

10th Percentile

$940

Median

$1,772

90th Percentile

$2,777

Score Distribution

415 diamonds scored across 4 quality tiers

Excellent

72 (17.3%)

Very Good

154 (37.1%)

Good

118 (28.4%)

Average

71 (17.1%)

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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