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Marquise|Natural|GIA

1.21ct J SI1 Marquise Natural Diamond

EX • J/SI1 • GIA 5241045555

Certificate GIA 5241045555

Diamond specifications and retailer prices

From £2,123 GBP
As of October 31, 2026
Save £1,834 GBP (46%) vs most expensive(unlock to see where)
14 retailers carry this diamond
Most expensive: £3,957 GBP at Helzberg Diamonds · As of November 3, 2026
View at Helzberg Diamonds

About this 1.21ct natural marquise diamond

This 1.21ct natural marquise sits in the classic one-carat band, graded J colour (near-colourless) and SI1 clarity (slightly-included), with a top-tier cut grade stated by the retailer rather than the lab and certified by GIA 5241045555. Listed at 14 retailers as of October 31, 2026, with prices from £2,123 to £3,957, a £1,834 spread on the same certified stone. Helzberg Diamonds lists it at £3,957. 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

1.21
Carat
J
Colour
SI1
Clarity
Excellent
Cut (retailer stated)

Specifications

Cut (retailer stated)Excellent
PolishVery Good
SymmetryExcellent
FluorescenceFaint
Crown angle39.63°
Pavilion angle40.08°
OriginNatural
Grading LabGIA
CertificateGIA 5241045555
Dimensions11.24 × 5.28 × 3.40 mm
L/W Ratio2.13
Culet sizeNone
Top View
11.24 mm5.28 mm1.21 ctJ / SI1
OriginNatural
CutExcellent
PolishVery Good
SymmetryExcellent
FluorescenceFaint
CertificateGIA 5241045555
Side View
Table 59.0%Crown 39.63°Girdle: STK-THKPavilion 40.08°Culet: NDepth 64.3%

Caratlytics Score

How it works →
B+
Very Good
Strong quality and value balance
Unlock full score analysis
See the detailed 0 to 100 score with Quality, Value, Certification & Market breakdown

Price History

Last verified: Oct 31
Current: £3,957 GBP|Low: £2,123 GBP|High: £4,291 GBP|Avg: £2,818 GBP|-7.8%
Helzberg Diamonds
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
November 5, 2026
Retailer 3£2,123 GBP
Retailer 2£2,174 GBP
Retailer 13£2,239 GBP
Retailer 8£2,249 GBP
Retailer 14£2,288 GBP
Retailer 12£2,433 GBP
Retailer 11£2,507 GBP
Retailer 9£2,674 GBP
Retailer 5£2,712 GBP
Retailer 10£2,736 GBP
Retailer 7£2,773 GBP
Retailer 6£3,580 GBP
Retailer 4£3,796 GBP
Helzberg Diamonds£3,957 GBP

35 data points across 14 retailers

14 retailers£2,123 GBP to £3,957 GBP

B+
Cheapest Retailer
-
£2,123 GBP
B+
Retailer 2
-
£2,174 GBP
View
B+
Retailer 3
-
£2,239 GBP
View
B+
Retailer 4
-
£2,249 GBP
View
B+
Retailer 5
-
£2,288 GBP
View
B
Retailer 6
-
£2,433 GBP
View
B
Retailer 7
-
£2,507 GBP
View
B
Retailer 8
-
£2,674 GBP
View
B
Retailer 9
-
£2,712 GBP
View
B
Retailer 10
-
£2,736 GBP
View
B
Retailer 11
-
£2,773 GBP
View
B
Retailer 12
-
£3,580 GBP
View
Retailer 13
-
£3,796 GBP
View
Price last confirmed 11 days ago
Most Expensive
B
Helzberg Diamonds
XZRLIKHGKLLLL · Nov 3
£3,957 GBP
$5,296 USD
View
13 more retailers have this diamond
Prices start from £2,123 GBPSave up to £1,834 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.

B+
1.21ct Marquise
£2,123 GBP