CaratHunter
Plans
Cushion|Lab Grown|IGI

4.05ct E SI1 Cushion Lab Grown Diamond

ID • E/SI1 • IGI LG788683920

Shape and cutting style on the report: Square cushion modified brilliant

Certificate IGI LG788683920

Diamond specifications and retailer prices

From £869 GBP
$1,165 USD
As of October 30, 2026
Save £3,661 GBP (81%) vs most expensive(unlock to see where)
11 retailers carry this diamond
Most expensive: £4,530 GBP at Brilliant Earth · As of October 29, 2026
View at Brilliant Earth

About this 4.05ct lab-grown cushion diamond

This 4.05ct lab-grown cushion sits in the three to five carat band, graded E colour (colourless) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI LG788683920 or 788683920. Listed at 11 retailers as of October 29, 2026, with prices from £869 to £4,530, a £3,661 spread on the same certified stone. Brilliant Earth lists it at £4,530. 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

4.05
Carat
E
Colour
SI1
Clarity
Ideal
Cut

Specifications

CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle34.2°
Pavilion angle41.3°
OriginLab Grown
Grading LabIGI
CertificateIGI LG788683920
Dimensions9.79 × 9.33 × 5.59 mm
L/W Ratio1.05
Girdle conditionFaceted
Culet sizeLarge
Cert comments
This Laboratory Grown Diamond was created by Chemical Vapor Deposition (CVD) growth process Type IIa
Top View
9.79 mm9.33 mm4.05 ctE / SI1
OriginLab Grown
CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI LG788683920
Side View
Table 59.0%Crown 34.2°Girdle: THK-VTKPavilion 41.3°Culet: LargeDepth 59.9%

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: Oct 30
Current: £4,530 GBP|Low: £369 GBP|High: £4,665 GBP|Avg: £1,388 GBP|-2.9%
Brilliant Earth
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
Retailer 8
Retailer 9
Retailer 10
Retailer 11
October 31, 2026
Retailer 3£369 GBP
Retailer 11£383 GBP
Retailer 8£607 GBP
Retailer 7£869 GBP
Retailer 10£918 GBP
Retailer 2£962 GBP
Retailer 4£972 GBP
Retailer 6£1,285 GBP
Retailer 9£2,045 GBP
Retailer 5£2,394 GBP
Brilliant Earth£4,530 GBP

41 data points across 11 retailers

11 retailers£869 GBP to £4,530 GBP

Retailer 1
-
£607 GBP
$813 USD
Price last confirmed 19 days ago
B+
Retailer 2
-
£869 GBP
$1,165 USD
View
A
Retailer 3
-
£918 GBP
$1,230 USD
View
A
Retailer 4
-
£962 GBP
€1,228 EUR
View
A
Retailer 5
-
£972 GBP
View
B+
Retailer 6
-
£1,099 GBP
$1,472 USD
View
B+
Retailer 7
-
£1,285 GBP
A$2,648 AUD
View
B
Retailer 8
-
£2,045 GBP
SGD 3,702 SGD
View
B
Retailer 9
-
£2,091 GBP
$2,802 USD
View
B
Retailer 10
-
£2,394 GBP
View
Most Expensive
B
Brilliant Earth
20696587A · Oct 29
£4,530 GBP
$6,070 USD
View
10 more retailers have this diamond
Prices start from £869 GBPSave up to £3,661 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
4.05ct Cushion
£869 GBP