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Round|Lab Grown|IGI

1.21ct G SI1 Round Lab Grown Diamond

ID • G/SI1 • IGI LG455028355

Shape and cutting style on the report: Round brilliant

Certificate IGI LG455028355

Diamond specifications and retailer prices

From £247 GBP
As of November 5, 2026
Save £620 GBP (72%) vs most expensive(unlock to see where)
7 retailers carry this diamond
Most expensive: £867 GBP at MOH London · As of November 5, 2026
View at MOH London

About this 1.21ct lab-grown round diamond

This 1.21ct lab-grown round sits in the classic one-carat band, graded G colour (near-colourless) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG455028355 or 455028355. Listed at 7 retailers as of November 5, 2026, with prices from £247 to £867, a £620 spread on the same certified stone. MOH London lists it at £867. 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

1.21
Carat
G
Colour
SI1
Clarity
Ideal
Cut

Specifications

CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle34.1°
Pavilion angle40.5°
OriginLab Grown
Grading LabIGI
CertificateIGI LG455028355
Dimensions6.86 × 6.82 × 4.17 mm
L/W Ratio1.01
Girdle conditionFaceted
Culet sizePointed
Cert comments
This Laboratory grown diamond was created by chemical vapor deposition process (CVD).
Top View
6.86 mm6.82 mm1.21 ctG / SI1
OriginLab Grown
CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG455028355
Side View
Table 57.5%Crown 34.1°Girdle: MED-STKPavilion 40.5°Culet: NoneDepth 61.0%

Caratlytics Score

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A
Excellent
Excellent quality and great value
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Price History

Last verified: Nov 5
Current: £867 GBP|Low: £197 GBP|High: £880 GBP|Avg: £407 GBP|-0.3%
MOH London
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
November 6, 2026
Retailer 5£197 GBP
Retailer 7£247 GBP
Retailer 3£312 GBP
Retailer 4£338 GBP
Retailer 2£405 GBP
Retailer 6£432 GBP
MOH London£867 GBP

42 data points across 7 retailers

7 retailers£247 GBP to £867 GBP

Retailer 1
-
£197 GBP
Price last confirmed 12 days ago
A
Retailer 2
-
£247 GBP
View
B+
Retailer 3
-
£312 GBP
View
B+
Retailer 4
-
£338 GBP
View
B+
Retailer 5
-
£405 GBP
View
B+
Retailer 6
-
£432 GBP
View
Most Expensive
B
MOH London
LG455028355 · Nov 5
£867 GBP
View
6 more retailers have this diamond
Prices start from £247 GBPSave up to £620 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
1.21ct Round
£247 GBP