2004 Australia 'The Kookaburra Proof Issue' 5-Coin Set - .999 Ag Perth Mint

'The Kookaburra Proof Issue Kilo Collection' 2004, a set of 5 x .999 silver proof coins struck by the Perth Mint comprising: 30 dollars diameter 101mm, weight 1 kilogram (32.15 troy oz.), 10 dollars 75.50mm, wt. 10oz (311g), 2 dollars 50.30mm, wt. 2oz (62.2g), 1 dollar 40.60mm, wt. 1oz (31.1g) & 50 cents 24.70mm x 24.70mm (square shape) wt. 1/2oz (15.5g); the obverses bear the Queen's portrait by Rank-Broadley & the reverses of all the coins except the 10 dollars depict a kookaburra perched on a branch; the reverse of the 10 dollar coin has the inscription 'EVOLUTION OF NUMBERS' and depicts a complex design of images and mathematical symbols representing the history of numbers (an abacus, fractions, square root & infinity signs, Pi, a pocket calculator etc); total .999 silver weight of the collection 45.65 troy oz; limited edition of 350 sets, individually encapsulated in a Perth Mint case of issue,