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Radiant|Lab Grown|GIA

1.21ct F SI1 Radiant Lab Grown Diamond

ID • F/SI1 • GIA 1505842159

Certificate GIA 1505842159

Diamond specifications and retailer prices

From £291 GBP
As of November 6, 2026
Save £855 GBP (75%) vs most expensive(unlock to see where)
5 retailers carry this diamond
Most expensive: £1,389 GBP at MOH London · As of November 5, 2026
View at MOH London

About this 1.21ct lab-grown radiant diamond

This 1.21ct lab-grown radiant sits in the classic one-carat band, graded F colour (colourless) and SI1 clarity (slightly-included), with a top-tier cut grade stated by the retailer rather than the lab and certified by GIA 1505842159. Listed at 5 retailers as of November 6, 2026, with a 294% 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

1.21
Carat
F
Colour
SI1
Clarity
Ideal
Cut (retailer stated)

Specifications

Cut (retailer stated)Ideal
PolishExcellent
SymmetryExcellent
FluorescenceNone
OriginLab Grown
Grading LabGIA
CertificateGIA 1505842159
Dimensions7.58 × 5.33 × 3.60 mm
L/W Ratio1.42
Girdle conditionPolished
Cert comments
This is a man-made diamond produced by CVD (Chemical Vapor Deposition) growth process and has evidence of post-growth treatments to change the color.
Key to symbols
Growth Remnant
Top View
7.58 mm5.33 mm1.21 ctF / SI1
OriginLab Grown
CutIdeal
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateGIA 1505842159
Side View
Table 66.0%CrownGirdle: STK-THKPavilionCulet: NoneDepth 67.6%

Caratlytics Score

How it works →
A
Excellent
Excellent quality and great value
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Price History

Last verified: Nov 6
Current: £1,389 GBP|Low: £291 GBP|High: £1,409 GBP|Avg: £766 GBP|-1.3%
MOH London
Retailer 2
Retailer 3
Retailer 4
November 6, 2026
Retailer 4£291 GBP
Retailer 2£580 GBP
Retailer 3£672 GBP
MOH London£1,389 GBP

41 data points across 4 retailers

5 retailers£291 GBP to £1,146 GBP

A
Cheapest Retailer
-
£291 GBP
Final sale: no returns
B+
Retailer 2
-
£580 GBP
View
B
Retailer 3
-
£672 GBP
View
B
Retailer 4
-
£1,146 GBP
View
Most Expensive
MOH London
1505842159 · Nov 5
£1,389 GBP
View
Price under review
4 more retailers have this diamond
Prices start from £291 GBPSave up to £855 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
1.21ct Radiant
£291 GBP