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Round|Lab Grown|IGI

1.20ct J SI1 Round Lab Grown Diamond

EX • J/SI1 • IGI LG451056607

Shape and cutting style on the report: Round brilliant

Certificate IGI LG451056607

Diamond specifications and retailer prices

From £513 GBP
As of November 5, 2026
Save £2,566 GBP (83%) vs most expensive(unlock to see where)
13 retailers carry this diamond
Most expensive: £3,079 GBP at MOH London · As of November 5, 2026
View at MOH London

About this 1.2ct lab-grown round diamond

This 1.2ct lab-grown round sits in the classic one-carat band, graded J colour (near-colourless) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG451056607 or 451056607. Listed at 13 retailers as of November 5, 2026, with prices from £513 to £3,079, a £2,566 spread on the same certified stone. MOH London lists it at £3,079. SI-grade stones are eye-clean roughly 60 to 70% of the time at this carat range. Check the inclusion plot on the cert and ask the retailer for high-resolution video before buying.

The 4Cs

1.20
Carat
J
Colour
SI1
Clarity
Excellent
Cut

Specifications

CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle32.2°
Pavilion angle41.5°
OriginLab Grown
Grading LabIGI
CertificateIGI LG451056607
Dimensions6.85 × 6.89 × 4.17 mm
L/W Ratio1.01
Girdle conditionFaceted
Culet sizePointed
Cert comments
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Top View
6.85 mm6.89 mm1.20 ctJ / SI1
OriginLab Grown
CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG451056607
Side View
Table 60.0%Crown 32.2°GirdlePavilion 41.5°Culet: NoneDepth 60.6%

Caratlytics Score

How it works →
A
Excellent
Excellent quality and great value
Unlock full score analysis
See the detailed 0 to 100 score with Quality, Value, Certification & Market breakdown

Price History

Last verified: Nov 5
Current: £3,079 GBP|Low: £513 GBP|High: £3,124 GBP|Avg: £1,280 GBP|-1.3%
MOH London
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
Retailer 8
Retailer 9
Retailer 10
Retailer 11
Retailer 12
November 6, 2026
Retailer 6£513 GBP
Retailer 7£828 GBP
Retailer 12£901 GBP
Retailer 11£928 GBP
Retailer 8£961 GBP
Retailer 10£961 GBP
Retailer 4£1,088 GBP
Retailer 5£1,102 GBP
Retailer 9£1,528 GBP
Retailer 2£1,633 GBP
Retailer 3£1,801 GBP
MOH London£3,079 GBP

45 data points across 12 retailers

13 retailers£513 GBP to £3,079 GBP

A
Cheapest Retailer
-
£513 GBP
B+
Retailer 2
-
£828 GBP
View
B+
Retailer 3
-
£901 GBP
View
B+
Retailer 4
-
£928 GBP
View
Final sale: no returns
Retailer 5
-
£961 GBP
View
Price last confirmed 25 days ago
B+
Retailer 6
-
£961 GBP
View
B+
Retailer 7
-
£1,088 GBP
View
B+
Retailer 8
-
£1,102 GBP
View
B
Retailer 9
-
£1,528 GBP
View
B
Retailer 10
-
£1,633 GBP
View
B
Retailer 11
-
£1,801 GBP
View
B
Retailer 12
-
£1,949 GBP
View
Most Expensive
B
MOH London
LG451056607 · Nov 5
£3,079 GBP
View
12 more retailers have this diamond
Prices start from £513 GBPSave up to £2,566 GBP

Carat Hunter is not affiliated with, endorsed by, or sponsored by any retailer listed. Retailer information is from publicly available sources and may not be current. Verify details directly with the retailer before purchasing. Return terms as we hold them. Check the retailer's own returns page before you buy.

A
1.20ct Round
£513 GBP