The Australian ten-ounce silver piece (abbreviated as 10 oz and designated with Ag for "silver") is a bullion and commemorative coin format used mostly by the Perth Mint, which only makes collector and bullion coins and other bullion products.
The Australian Silver Kookaburra series was introduced in 1990 by the Perth Mint in the silver one-ounce format. Subsequently, the range was expanded in 1991 to also include 2oz silver, 10oz silver and 1 kg silver; much later, gold and platinum formats were also introduced.
The coins in the series have legal tender status in Australia and are one of very few legal tender bullion silver coins to change their design every year, always featuring a kookaburra - a bird native to Australia, which is the largest member of the kingfisher family and the national bird of Australia. This and their limited annual mintage may, unlike for many other bullion coins, raise their numismatic value over the value of silver used.
This 10 oz silver bullion coin is part of the 30th Anniversary of the Australian Kookaburra coin range by the Perth Mint.
The Mint says about it:
A laughing kookaburra, the largest member of the kingfisher species, is synonymous with the Australian outback. This spectacular 30th anniversary coin includes a special anniversary obverse design.
The coin’s reverse depicts a kookaburra perched on a roof at dawn with stylised rays of light in the background. The obverse bears Stuart Devlin’s depiction of a kookaburra on a tree stump surrounded by native foliage, as it appeared on The Perth Mint’s 1990 Australian Kookaburra Silver Bullion Coin. | 
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