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

As of October 2026, 1.50 to 1.99ct D SI1 lab grown radiant diamonds typically cost £168 GBP to £877 GBP, with a median price of £504 GBP. There are currently 110 diamonds matching this specification available across retailers.

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

About 27% of these diamonds are available at multiple retailers, with an average price spread of 96%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct D SI1 Lab Grown Radiant

Quick answer

As of October 2026, there are 110 lab grown radiant diamonds with D colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £168 GBP to £877 GBP, with a median of £504 GBP. At least 36 retailers stock this exact specification, and 27% of the stones appear at more than one of them, with an average price spread of 96%. Half of all listings fall between £172 GBP and £457 GBP per carat. The same specification in natural form lists at a median of about £4,392 GBP per carat. Over the last 30 days the median price moved +11.7% and the number of listings moved +23.9%.

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 lab grown stones in the index: 474 USD per carat, -2.1% 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

110

Lowest Price

£116 GBP

Highest Price

£2,274 GBP

Average Price

£547 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

27.3%

Price Spread

96.0%

30-Day Price Trend

+11.7%

30-Day Supply Change

+23.9%

Volatility (30d)

0.06

Price Range

Price per carat distribution across retailers

$394/ct

10th Percentile

$139

Median

$394

90th Percentile

$830

Score Distribution

183 diamonds scored across 4 quality tiers

Excellent

38 (20.8%)

Very Good

24 (13.1%)

Good

62 (33.9%)

Average

59 (32.2%)

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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