The Cook Islands, a sovereign state in free association with New Zealand, uses two official legal tender currencies. The New Zealand Dollar circulates in parallel with the local Cook Islands Dollar; at the same time, the government also authorises many legal tender coins in the Cook Islands Dollar currency for collector's purposes.
Collector coins are dedicated to historical or general popular culture themes not related to the country itself. Many of them are in standard bullion sizes, but the silver $5 (Five Dollars) - like this coin - are not; their weight is more than a half ounce but less than one ounce, and is "metric".
This coin is part of a heart-shaped series issued (almost) annually, with a new design every year.
The Mint says about it:
It’s time for love. This heart shaped coin in proof finish is the perfect way to express your feelings to the beloved ones. The timeless but modern twist is created by the application of crystals and the brilliant colouring combined with a water drop relief effect. Struck in 20 grams of pure silver, this is the perfect gift for whoever you wish to show your love to. | 
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