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Round|Lab Grown|IGI

1.21ct I SI1 Round Lab Grown Diamond

EX • I/SI1 • IGI LG425066489

Shape and cutting style on the report: Round brilliant

Certificate IGI LG425066489

Diamond specifications and retailer prices

From £453 GBP
As of November 5, 2026
Save £2,942 GBP (87%) vs most expensive(unlock to see where)
13 retailers carry this diamond
Most expensive: £3,395 GBP at MOH London · As of November 3, 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 I colour (near-colourless) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG425066489 or 425066489. Listed at 13 retailers as of November 3, 2026, with prices from £453 to £3,395, a £2,942 spread on the same certified stone. MOH London lists it at £3,395. 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
I
Colour
SI1
Clarity
Excellent
Cut

Specifications

CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle31.6°
Pavilion angle40.9°
OriginLab Grown
Grading LabIGI
CertificateIGI LG425066489
Dimensions6.96 × 6.98 × 4.13 mm
L/W Ratio1.00
Girdle conditionFaceted
Culet sizePointed
Cert comments
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Top View
6.96 mm6.98 mm1.21 ctI / SI1
OriginLab Grown
CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG425066489
Side View
Table 58.5%Crown 31.6°GirdlePavilion 40.9°Culet: NoneDepth 59.3%

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: £3,395 GBP|Low: £453 GBP|High: £3,440 GBP|Avg: £1,559 GBP|-1.1%
MOH London
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
Retailer 8
Retailer 9
Retailer 10
Retailer 11
November 6, 2026
Retailer 6£453 GBP
Retailer 5£1,025 GBP
Retailer 11£1,115 GBP
Retailer 10£1,148 GBP
Retailer 7£1,189 GBP
Retailer 9£1,189 GBP
Retailer 2£1,547 GBP
Retailer 8£1,877 GBP
Retailer 4£2,014 GBP
Retailer 3£2,228 GBP
MOH London£3,395 GBP

46 data points across 11 retailers

13 retailers£453 GBP to £3,395 GBP

A
Cheapest Retailer
-
£453 GBP
B+
Retailer 2
-
£1,025 GBP
View
B+
Retailer 3
-
£1,115 GBP
View
B+
Retailer 4
-
£1,148 GBP
View
Final sale: no returns
B+
Retailer 5
-
£1,189 GBP
View
Retailer 6
-
£1,189 GBP
View
Price last confirmed 25 days ago
B
Retailer 7
-
£1,315 GBP
View
B+
Retailer 8
-
£1,547 GBP
View
B
Retailer 9
-
£1,877 GBP
View
B
Retailer 10
-
£2,014 GBP
View
B
Retailer 11
-
£2,158 GBP
View
B
Retailer 12
-
£2,228 GBP
View
Most Expensive
B
MOH London
LG425066489 · Nov 3
£3,395 GBP
View
12 more retailers have this diamond
Prices start from £453 GBPSave up to £2,942 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
£453 GBP