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Round|Lab Grown|IGI

1.20ct D SI1 Round Lab Grown Diamond

EX • D/SI1 • IGI LG517200392

Shape and cutting style on the report: Round brilliant

Certificate IGI LG517200392

Diamond specifications and retailer prices

From £328 GBP
$437 USD
As of October 30, 2026
Save £840 GBP (72%) vs most expensive(unlock to see where)
13 retailers carry this diamond
Most expensive: £1,428 GBP at MOH London · As of October 29, 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 D colour (colourless) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG517200392 or 517200392. Listed at 13 retailers as of October 24, 2026, with a 256% spread between the cheapest and most expensive listing. That is exactly the kind of price-discovery gap Carat Hunter was built to surface. 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
D
Colour
SI1
Clarity
Excellent
Cut

Specifications

CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle36.1°
Pavilion angle41.1°
OriginLab Grown
Grading LabIGI
CertificateIGI LG517200392
Dimensions6.74 × 6.70 × 4.23 mm
L/W Ratio1.01
Girdle conditionFaceted
Culet sizePointed
Cert comments
As Grown - No indication of post-growth treatment This Laboratory Grown Diamond was created by High Pressure High Temperature (HPHT) growth process Type II
Top View
6.74 mm6.70 mm1.20 ctD / SI1
OriginLab Grown
CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG517200392
Side View
Table 59.5%Crown 36.1°Girdle: MED-STKPavilion 41.1°Culet: NoneDepth 62.9%

Caratlytics Score

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B+
Very Good
Strong quality and value balance
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See the detailed 0 to 100 score with Quality, Value, Certification & Market breakdown

Price History

Last verified: Oct 30
Current: £1,428 GBP|Low: £234 GBP|High: £1,437 GBP|Avg: £559 GBP|+0.5%
MOH London
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
Retailer 8
Retailer 9
Retailer 10
Retailer 11
Retailer 12
Retailer 13
Retailer 14
October 30, 2026
Retailer 11£293 GBP
Retailer 3£328 GBP
Retailer 14£328 GBP
Retailer 6£338 GBP
Retailer 5£363 GBP
Retailer 12£363 GBP
Retailer 8£447 GBP
Retailer 10£473 GBP
Retailer 7£559 GBP
Retailer 13£577 GBP
Retailer 2£594 GBP
Retailer 9£1,020 GBP
Retailer 4£1,168 GBP
MOH London£1,428 GBP

44 data points across 14 retailers

13 retailers£328 GBP to £1,168 GBP

Retailer 1
-
£293 GBP
$390 USD
Price last confirmed 7 days ago
B+
Retailer 2
-
£328 GBP
$437 USD
View
Final sale: no returns
B+
Retailer 3
-
£328 GBP
$437 USD
View
B+
Retailer 4
-
£338 GBP
$450 USD
View
B+
Retailer 5
-
£363 GBP
$484 USD
View
Retailer 6
-
£447 GBP
$595 USD
View
Price last confirmed 8 days ago
B+
Retailer 7
-
£473 GBP
$630 USD
View
B
Retailer 8
-
£559 GBP
€709 EUR
View
B
Retailer 9
-
£577 GBP
$768 USD
View
B
Retailer 10
-
£594 GBP
View
B
Retailer 11
-
£1,020 GBP
$1,358 USD
View
B
Retailer 12
-
£1,168 GBP
$1,556 USD
View
Most Expensive
MOH London
LG517200392 · Oct 29
£1,428 GBP
View
Price under review
12 more retailers have this diamond
Prices start from £328 GBPSave up to £840 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.

B+
1.20ct Round
£328 GBP