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Radiant|Natural|GIA

2.51ct I SI1 Radiant Natural Diamond

EX • I/SI1 • GIA 1518171703

Certificate GIA 1518171703

Diamond specifications and retailer prices

From $17,254 AUD
$12,120 USD
As of November 2, 2026
Save $7,544 AUD (30%) vs most expensive(unlock to see where)
9 retailers carry this diamond
Most expensive: $27,443 AUD at NZ Jewellers · As of September 27, 2026
View at NZ Jewellers

About this 2.51ct natural radiant diamond

This 2.51ct natural radiant sits in the two to three carat band, graded I 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 1518171703. Listed at 9 retailers as of November 1, 2026, with a 44% 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

2.51
Carat
I
Colour
SI1
Clarity
Excellent
Cut (retailer stated)

Specifications

Cut (retailer stated)Excellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
Crown angle44.73°
Pavilion angle31.36°
OriginNatural
Grading LabGIA
CertificateGIA 1518171703
Dimensions8.69 × 6.69 × 4.60 mm
L/W Ratio1.30
Girdle conditionVery Thick
Key to symbols
Feather, Cavity, Needle
Top View
8.69 mm6.69 mm2.51 ctI / SI1
OriginNatural
CutExcellent
PolishExcellent
SymmetryExcellent
FluorescenceNone
CertificateGIA 1518171703
Side View
Table 66.0%Crown 44.73°GirdlePavilion 31.36°CuletDepth 68.7%

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 2
Current: $18,268 AUD|Low: $17,254 AUD|High: $26,026 AUD|Avg: $19,810 AUD|-4.7%
Retailer 1
Retailer 2
Retailer 3
Retailer 4
Retailer 5
Retailer 6
Retailer 7
November 2, 2026
Retailer 3$17,254 AUD
Retailer 4$17,264 AUD
Retailer 1$18,268 AUD
Retailer 7$18,552 AUD
Retailer 6$19,293 AUD
Retailer 5$20,308 AUD
Retailer 2$24,798 AUD

37 data points across 7 retailers

9 retailers$17,254 AUD to $24,798 AUD

A
Cheapest Retailer
-
$17,254 AUD
$12,120 USD
Retailer 2
-
$17,264 AUD
View
Price last confirmed 9 days ago
A
Retailer 3
-
$18,268 AUD
£10,104 GBP
View
Retailer 4
-
$19,387 AUD
$13,618 USD
View
Price last confirmed 32 days ago
Retailer 5
-
$19,690 AUD
$13,831 USD
View
Price last confirmed 37 days ago
Retailer 6
-
$19,690 AUD
$13,831 USD
View
Price last confirmed 26 days ago
A
Retailer 7
-
$24,798 AUD
£13,716 GBP
View
Retailer 8
-
$27,443 AUD
$19,277 USD
View
Price last confirmed 26 days ago
Most Expensive
NZ Jewellers
4d56b567-6ce3-4faf-84e9-24a3f1d341c9 · Sep 27
$27,443 AUD
$19,277 USD
View
Price last confirmed 36 days ago
8 more retailers have this diamond
Prices start from $17,254 AUDSave up to $7,544 AUD

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
2.51ct Radiant
$17,254 AUD