Round|Natural|IGI

1.28ct M SI1 Round Natural Diamond

EX • M/SI1 • IGI 726509637

Shape and cutting style on the report: Round brilliant

Certificate IGI 726509637

Diamond specifications and retailer prices

From £928 GBP
As of October 30, 2026
Save £267 GBP (22%) vs most expensive(unlock to see where)
7 retailers carry this diamond
Most expensive: £2,138 GBP at NZ Jewellers · As of October 30, 2026
View at NZ Jewellers

About this 1.28ct natural round diamond

This 1.28ct natural round sits in the one-and-a-quarter to one-and-a-half carat band, graded M colour (faint-tinted) and SI1 clarity (slightly-included), with a top-tier cut grade and certified by IGI 726509637. Listed at 7 retailers as of October 30, 2026, with a 29% 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

1.28
Carat
M
Colour
SI1
Clarity
Excellent
Cut

Specifications

CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle36.1°
Pavilion angle40.7°
OriginNatural
Grading LabIGI
CertificateIGI 726509637
Dimensions6.90 × 6.91 × 4.33 mm
L/W Ratio1.00
Culet sizePointed
Top View
6.90 mm6.91 mm1.28 ctM / SI1
OriginNatural
CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateIGI 726509637
Side View
Table 57.0%Crown 36.1°Girdle: MED-STKPavilion 40.7°Culet: NoneDepth 62.8%

Caratlytics Score

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A
Excellent
Excellent quality and great value
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Price History

Last verified: Oct 30
Current: £2,138 GBP|Low: £658 GBP|High: £2,138 GBP|Avg: £1,072 GBP
NZ Jewellers
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
Retailer 8
November 6, 2026
Retailer 8£658 GBP
Retailer 3£869 GBP
Retailer 5£877 GBP
Retailer 4£911 GBP
Retailer 6£928 GBP
Retailer 7£970 GBP
Retailer 2£1,195 GBP
NZ Jewellers£2,138 GBP

33 data points across 8 retailers

7 retailers£928 GBP to £1,195 GBP

Retailer 1
-
£869 GBP
Price last confirmed 7 days ago
Retailer 2
-
£877 GBP
View
Price last confirmed 8 days ago
Retailer 3
-
£911 GBP
View
Price last confirmed 8 days ago
A
Retailer 4
-
£928 GBP
View
Retailer 5
-
£970 GBP
View
Price last confirmed 6 days ago
A
Retailer 6
-
£1,195 GBP
View
Most Expensive
NZ Jewellers
47ac3e65-5c01-45f2-a94c-bb7beb97ae69 · Oct 30
£2,138 GBP
$2,878 USD
View
Price last confirmed 7 days ago
6 more retailers have this diamond
Prices start from £928 GBPSave up to £267 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
1.28ct Round
£928 GBP