Radiant|Lab Grown|IGI

1.78ct H SI2 Radiant Lab Grown Diamond

ID • H/SI2 • IGI LG512231558

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

Certificate IGI LG512231558

Diamond specifications and retailer prices

From $1,876 NZD
As of November 6, 2026
Save $3,712 NZD (66%) vs most expensive(unlock to see where)
9 retailers carry this diamond
Most expensive: $8,527 NZD at MOH London · As of October 27, 2026
View at MOH London

About this 1.78ct lab-grown radiant diamond

This 1.78ct lab-grown radiant sits in the one-and-a-half to two carat band, graded H colour (near-colourless) and SI2 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG512231558 or 512231558. Listed at 9 retailers as of November 6, 2026, with a 198% 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

1.78
Carat
H
Colour
SI2
Clarity
Ideal
Cut

Specifications

CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle43°
Pavilion angle29.7°
OriginLab Grown
Grading LabIGI
CertificateIGI LG512231558
Dimensions8.12 × 5.95 × 4.04 mm
L/W Ratio1.36
Culet sizePointed
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
8.12 mm5.95 mm1.78 ctH / SI2
OriginLab Grown
CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG512231558
Side View
Table 65.0%Crown 43°Girdle: ThickPavilion 29.7°Culet: NoneDepth 67.9%

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 6
Current: $8,527 NZD|Low: $1,876 NZD|High: $8,630 NZD|Avg: $4,314 NZD|-0.9%
MOH London
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
Retailer 8
Retailer 9
Retailer 10
October 30, 2026
Retailer 2$1,876 NZD
Retailer 3$2,571 NZD
Retailer 7$2,796 NZD
Retailer 4$2,982 NZD
Retailer 10$3,305 NZD
Retailer 9$4,080 NZD
Retailer 5$4,705 NZD
Retailer 8$5,412 NZD
Retailer 6$5,588 NZD
MOH London$8,527 NZD

14 data points across 10 retailers

9 retailers$1,876 NZD to $5,588 NZD

A
Cheapest Retailer
-
$1,876 NZD
A
Retailer 2
-
$2,571 NZD
View
A
Retailer 3
-
$2,796 NZD
View
Retailer 4
-
$2,982 NZD
View
Price last confirmed 26 days ago
B+
Retailer 5
-
$2,982 NZD
View
B
Retailer 6
-
$4,705 NZD
View
B
Retailer 7
-
$5,412 NZD
View
B
Retailer 8
-
$5,588 NZD
View
Most Expensive
MOH London
LG512231558 · Oct 27
$8,527 NZD
£3,722 GBP
View
Price last confirmed 11 days ago
8 more retailers have this diamond
Prices start from $1,876 NZDSave up to $3,712 NZD

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
1.78ct Radiant
$1,876 NZD