It is the rarest New Zealand circulation coin known, struck with both New Zealand and UK designs, now formally authenticated by Numismatic Guaranty Company (NGC), the world's leading third-party authority on mint errors, as Mint Error - Genuine. 

NGC: A Mule is a coin that has an obverse and reverse that were not intended to go together

Technical Analysis

The coin is struck on a standard milled New Zealand Two Dollars planchet, complete with its intact security groove. Rather than the English inscription “NEW ZEALAND ELIZABETH II” found on all standard $2 coins, the obverse instead has the following Latin legend:

ELIZABETH · II · D · G · REG · F · D · 2002

Translated as Dei Gratia Regina, Fidei Defensor, this inscription is found on coins from the United Kingdom. Comprehensive die analysis of all 2002 issues struck at the Royal Mint—where New Zealand’s $2 coins were also produced—confirms that the obverse die matches those of the UK Two Pence denomination for that year.

Metallurgical and Authentication

Although no official mint documentation acknowledging the error has surfaced, non-destructive XRF metallurgical analysis of the planchet confirms the following composition:

Copper (Cu): ~97.0%

Nickel (Ni): ~2.2%

Zinc (Zn): ~0.3%

Gold (Au): trace ~0.2%

The coin has been formally certified as Mint Error - Genuine and sealed in a tamper-proof holder by NGC.

No verified second example has surfaced in the two decades since its striking, rendering this example apparently UNIQUE.

A True Circulation Mule

According to long-time coin collector Joshua Lee, “What transforms this ordinary looking coin from everyday spending money into a major rarity is not that it was made out of gold or silver or even a limited edition collector's set preserved in pristine condition, but the simple fact that it is a coin that should not have existed". 

In coin collecting, a mule error that occurs on a legal tender coin used in actual circulation is among the most valuable and sought-after of all mint errors.

While Aventine previously sold the famed Discovery Example of the 2024 New Zealand–Solomon Islands mule at the Official ANE Sale that year, that issue—although legal tender—was a legal tender commemorative release by NZ Post and was never intended to circulate.

As Lee further notes, “Whether the result of a mix-up or “mint sport”, a true legal tender circulation mule represents one of the most exceptional rarities in the New Zealand coinage series”. 

A New Zealand Highlight on the World Stage

At the New York International Numismatic Convention (NYINC) 2026, Aventine is pleased to present the Discovery Example of New Zealand’s rarest circulation coin through Spink Auctions.

Anticipated to attract substantial interest from collectors of the Commonwealth series worldwide, it is estimated to fetch up to $10,000 USD.

Bidding Representation:

JLee@Spink.com

Found Another One?

Email: mule@Aventine.co.nz