How much does a 1.50 to 1.99ct D SI1 natural radiant diamond cost?

As of October 2026, 1.50 to 1.99ct D SI1 natural radiant diamonds typically cost £4,839 GBP to £12,567 GBP, with a median price of £7,866 GBP. There are currently 68 diamonds matching this specification available across retailers.

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

About 34% of these diamonds are available at multiple retailers, with an average price spread of 45%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct D SI1 Natural Radiant

Quick answer

As of October 2026, there are 68 natural radiant diamonds with D colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £4,839 GBP to £12,567 GBP, with a median of £7,866 GBP. At least 61 retailers stock this exact specification, and 34% of the stones appear at more than one of them, with an average price spread of 45%. Half of all listings fall between £3,544 GBP and £5,516 GBP per carat. The same specification in lab grown form lists at a median of about £296 GBP per carat. Over the last 30 days the median price moved -2.2% and the number of listings moved +5.2%.

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

Lowest Price

£3,258 GBP

Highest Price

£21,518 GBP

Average Price

£8,461 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

33.9%

Price Spread

44.9%

30-Day Price Trend

-2.2%

30-Day Supply Change

+5.2%

Volatility (30d)

0.01

Price Range

Price per carat distribution across retailers

$5,849/ct

10th Percentile

$3,908

Median

$5,849

90th Percentile

$9,033

Score Distribution

189 diamonds scored across 4 quality tiers

Excellent

20 (10.6%)

Very Good

53 (28.0%)

Good

37 (19.6%)

Average

79 (41.8%)

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Consider Instead

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

D SI2SI2 inclusions are not visible without magnification

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Lab-Grown D 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