How much does a 1.00 to 1.49ct I SI1 lab grown heart diamond cost?

As of September 2026, 1.00 to 1.49ct I SI1 lab grown heart diamonds typically cost £716 GBP to £1,568 GBP, with a median price of £1,057 GBP. There are currently 76 diamonds matching this specification available across retailers.

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

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1.00 to 1.49ct I SI1 Lab Grown Heart

Quick answer

As of September 2026, there are 76 lab grown heart diamonds with I colour and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £716 GBP to £1,568 GBP, with a median of £1,057 GBP. At least 14 retailers stock this exact specification. Half of all listings fall between £979 GBP and £1,347 GBP per carat. The same specification in natural form lists at a median of about £1,742 GBP per carat.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, August 2026: natural diamonds at 2,184 USD per carat and lab-grown at 464 USD per carat, a natural to lab ratio of 4.7 to 1. Heart lab grown stones in the index: 440 USD per carat, -9.4% month on month. See the full index release

Figures come from live listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: September 2026

Available

Lowest Price

£564 GBP

Highest Price

£3,667 GBP

Average Price

£1,220 GBP

Market Intelligence

Retailers Selling

Price Spread

37.1%

Price Range

Price per carat distribution across retailers

$1,336/ct

10th Percentile

$793

Median

$1,336

90th Percentile

$2,438

Score Distribution

76 diamonds scored across 4 quality tiers

Excellent

7 (9.2%)

Very Good

6 (7.9%)

Good

47 (61.8%)

Average

16 (21.1%)

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J SI1J colour is visually identical to I to the naked eye

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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