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

As of October 2026, 1.50 to 1.99ct D SI1 lab grown round diamonds typically cost £168 GBP to £1,214 GBP, with a median price of £578 GBP. There are currently 538 diamonds matching this specification available across retailers.

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

About 29% of these diamonds are available at multiple retailers, with an average price spread of 83%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct D SI1 Lab Grown Round

Quick answer

As of October 2026, there are 538 lab grown round 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 £1,214 GBP, with a median of £578 GBP. At least 43 retailers stock this exact specification, and 29% of the stones appear at more than one of them, with an average price spread of 83%. Half of all listings fall between £181 GBP and £422 GBP per carat. The same specification in natural form lists at a median of about £5,027 GBP per carat. Over the last 30 days the median price moved +2.2% and the number of listings moved +9.5%.

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. Round lab grown stones in the index: 414 USD per carat, -5.0% 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

538

Lowest Price

£115 GBP

Highest Price

£2,213 GBP

Average Price

£622 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

29.3%

Price Spread

82.7%

30-Day Price Trend

+2.2%

30-Day Supply Change

+9.5%

Volatility (30d)

0.03

Price Range

Price per carat distribution across retailers

$388/ct

10th Percentile

$154

Median

$388

90th Percentile

$809

Score Distribution

1.1K diamonds scored across 4 quality tiers

Excellent

262 (23.1%)

Very Good

127 (11.2%)

Good

331 (29.2%)

Average

413 (36.5%)

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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