Radiant|Lab Grown|IGI

12.78ct F SI1 Radiant Lab Grown Diamond

ID • F/SI1 • IGI LG591336712

Shape and cutting style on the report: Cut cornered rectangular modified brilliant

Certificate IGI LG591336712

Diamond specifications and retailer prices

From $1,523 USD
£1,199 GBP
As of November 1, 2026
Save $2,031 USD (57%) vs most expensive(unlock to see where)
13 retailers carry this diamond
Most expensive: $10,944 USD at Adiamor · As of October 31, 2026
View at Adiamor

About this 12.78ct lab-grown radiant diamond

This 12.78ct lab-grown radiant sits in the over five carat band, graded F colour (colourless) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG591336712 or 591336712. Listed at 13 retailers as of November 1, 2026, with a 133% 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

12.78
Carat
F
Color
SI1
Clarity
Ideal
Cut

Specifications

CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle44.8°
Pavilion angle34°
OriginLab Grown
Grading LabIGI
CertificateIGI LG591336712
Dimensions16.82 × 11.37 × 7.51 mm
L/W Ratio1.48
Cert comments
This Laboratory Grown Diamond was created by Chemical Vapor Deposition (CVD) growth process and may include post-growth treatment Type IIa
Top View
16.82 mm11.37 mm12.78 ctF / SI1
OriginLab Grown
CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG591336712
Side View
Table 65.0%Crown 44.8°Girdle: Slightly ThickPavilion 34°Culet: NoneDepth 66.1%

Caratlytics Score

How it works →
A
Excellent
Excellent quality and great value
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Price History

Last verified: Nov 1
Current: $10,944 USD|Low: $1,523 USD|High: $22,884 USD|Avg: $6,340 USD|-52.2%
Adiamor
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
Retailer 15
Retailer 16
November 2, 2026
Retailer 10$1,523 USD
Retailer 6$1,635 USD
Retailer 5$1,779 USD
Retailer 13$1,896 USD
Retailer 14$2,065 USD
Retailer 16$2,227 USD
Retailer 15$2,499 USD
Retailer 2$2,665 USD
Retailer 9$2,982 USD
Retailer 11$3,010 USD
Retailer 12$3,269 USD
Retailer 3$3,554 USD
Retailer 4$6,085 USD
Adiamor$10,944 USD
Retailer 7$20,500 USD
Retailer 8$20,550 USD

7 data points across 16 retailers

13 retailers$1,523 USD to $3,554 USD

A
Cheapest Retailer
-
$1,523 USD
£1,199 GBP
A
Retailer 2
-
$1,635 USD
View
A
Retailer 3
-
$1,779 USD
View
A
Retailer 4
-
$1,896 USD
View
A
Retailer 5
-
$2,065 USD
View
B+
Retailer 6
-
$2,227 USD
HK$17,400 HKD
View
B+
Retailer 7
-
$2,499 USD
View
B+
Retailer 8
-
$2,665 USD
£2,098 GBP
View
B+
Retailer 9
-
$2,982 USD
View
B
Retailer 10
-
$3,010 USD
€2,867 EUR
View
B+
Retailer 11
-
$3,269 USD
View
B
Retailer 12
-
$3,554 USD
View
Most Expensive
Adiamor
D-82832577 · Oct 31
$10,944 USD
View
Price under review
12 more retailers have this diamond
Prices start from $1,523 USDSave up to $2,031 USD

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
12.78ct Radiant
$1,523 USD