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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 $2,173 AUD
£1,199 GBP
As of November 2, 2026
Save $2,898 AUD (57%) vs most expensive(unlock to see where)
13 retailers carry this diamond
Most expensive: $15,616 AUD at Adiamor · As of November 2, 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
Colour
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
Unlock full score analysis
See the detailed 0 to 100 score with Quality, Value, Certification & Market breakdown

Price History

Last verified: Nov 2
Current: $15,616 AUD|Low: $2,173 AUD|High: $32,653 AUD|Avg: $9,047 AUD|-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 2$2,173 AUD
Retailer 6$2,333 AUD
Retailer 5$2,538 AUD
Retailer 13$2,705 AUD
Retailer 14$2,947 AUD
Retailer 16$3,178 AUD
Retailer 15$3,566 AUD
Retailer 9$3,803 AUD
Retailer 10$4,255 AUD
Retailer 11$4,295 AUD
Retailer 12$4,665 AUD
Retailer 3$5,071 AUD
Retailer 4$8,683 AUD
Adiamor$15,616 AUD
Retailer 7$29,252 AUD
Retailer 8$29,323 AUD

7 data points across 16 retailers

13 retailers$2,173 AUD to $5,071 AUD

A
Cheapest Retailer
-
$2,173 AUD
£1,199 GBP
A
Retailer 2
-
$2,333 AUD
$1,635 USD
View
A
Retailer 3
-
$2,538 AUD
$1,779 USD
View
A
Retailer 4
-
$2,705 AUD
$1,896 USD
View
A
Retailer 5
-
$2,947 AUD
$2,065 USD
View
B+
Retailer 6
-
$3,178 AUD
HK$17,400 HKD
View
B+
Retailer 7
-
$3,566 AUD
$2,499 USD
View
B+
Retailer 8
-
$3,803 AUD
£2,098 GBP
View
B+
Retailer 9
-
$4,255 AUD
$2,982 USD
View
B
Retailer 10
-
$4,295 AUD
€2,867 EUR
View
B+
Retailer 11
-
$4,665 AUD
$3,269 USD
View
B
Retailer 12
-
$5,071 AUD
$3,554 USD
View
Most Expensive
Adiamor
D-82832577 · Nov 2
$15,616 AUD
$10,944 USD
View
Price under review
12 more retailers have this diamond
Prices start from $2,173 AUDSave up to $2,898 AUD

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
$2,173 AUD