How much does a 1.00 to 1.49ct I SI2 lab grown heart diamond cost?

As of October 2026, 1.00 to 1.49ct I SI2 lab grown heart diamonds typically cost £524 GBP to £1,195 GBP, with a median price of £879 GBP. There are currently 5 diamonds matching this specification available across retailers.

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

About 69% of these diamonds are available at multiple retailers, with an average price spread of 71%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct I SI2 Lab Grown Heart

Quick answer

As of October 2026, there are 5 lab grown heart diamonds with I colour and SI2 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £524 GBP to £1,195 GBP, with a median of £879 GBP. At least 12 retailers stock this exact specification, and 69% of the stones appear at more than one of them, with an average price spread of 71%. Half of all listings fall between £734 GBP and £1,601 GBP per carat. The same specification in natural form lists at a median of about £1,632 GBP per carat. Over the last 30 days the median price moved -5.9% and the number of listings moved +20.8%.

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

£518 GBP

Highest Price

£2,894 GBP

Average Price

£848 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

69.2%

Price Spread

71.0%

30-Day Price Trend

-5.9%

30-Day Supply Change

+20.8%

Volatility (30d)

0.02

Price Range

Price per carat distribution across retailers

$1,626/ct

10th Percentile

$873

Median

$1,626

90th Percentile

$2,252

Score Distribution

9 diamonds scored across 4 quality tiers

Excellent

2 (22.2%)

Very Good

3 (33.3%)

Good

1 (11.1%)

Average

3 (33.3%)

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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