How much does a 1.50 to 1.99ct I SI1 lab grown heart diamond cost?

As of October 2026, 1.50 to 1.99ct I SI1 lab grown heart diamonds typically cost £137 GBP to £2,384 GBP, with a median price of £473 GBP. There are currently 2 diamonds matching this specification available across retailers.

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

About 55% of these diamonds are available at multiple retailers, with an average price spread of 183%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.50 to 1.99ct I SI1 Lab Grown Heart

Quick answer

As of October 2026, there are 2 lab grown heart diamonds with I colour and SI1 clarity in the 1.50 to 1.99ct range available across retailers worldwide. Prices typically run £137 GBP to £2,384 GBP, with a median of £473 GBP. At least 22 retailers stock this exact specification, and 55% of the stones appear at more than one of them, with an average price spread of 183%. Half of all listings fall between £145 GBP and £776 GBP per carat. The same specification in natural form lists at a median of about £2,708 GBP per carat. Over the last 30 days the median price moved -17.7% and the number of listings moved +17.1%.

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. Heart lab grown stones in the index: 421 USD per carat, -1.8% 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

£136 GBP

Highest Price

£5,889 GBP

Average Price

£1,027 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

55.0%

Price Spread

182.8%

30-Day Price Trend

-17.7%

30-Day Supply Change

+17.1%

Volatility (30d)

0.04

Price Range

Price per carat distribution across retailers

$462/ct

10th Percentile

$134

Median

$462

90th Percentile

$2,055

Score Distribution

7 diamonds scored across 3 quality tiers

Very Good

4 (57.1%)

Good

2 (28.6%)

Average

1 (14.3%)

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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