Niue, a sovereign state in free association with New Zealand, uses two official legal tender currencies. The New Zealand Dollar is the circulation currency for daily transactions, while the government also authorises legal tender coins in the Niue Dollar currency for collector's purposes.
A number of mints issue a large variety of coins under the authority of Niue. Most of these are commemorative and collector issues dedicated to historical or general popular culture themes not related to Niue itself. Many of them are in standard bullion sizes, including one ounce of gold (abbreviated as 1 oz Au, where "Au" comes from the Latin word for gold, Aurum). Those issued at prices much higher than their bullion value are separately listed in the Non-Circulating Legal Tender (NCLT) gold ounce section of the site.
Unlike them, this coin is targeted at bullion investors and was initially released at a price close to the value of its precious metal content.
This is the second design in the Magnum Opus series of premium bullion coins by the Pressburg Mint, and the first one issued for Niue (the first edition was for Tokelau). The coins in the series have a new design every year and are about the beauty of mathematics.
The mint says about it:
Mathematics is the language of nature and the Golden Ratio has baffled scientists for centuries. Showing up everywhere from snail shells to financial markets and all the way to galaxies, this peculiar law of nature seeps into everything. | 
Buy this online from APMEX
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