Yes. The platypus is on the Australian 20c coin. The image was designed and sculpted by Stuart Devlin. See the related link below for a picture.
Yes. The platypus is endemic to Australia, meaning it is not found in any other country.
If you refer to the collector value of 1954 Australian coins, not much. Any value would be dependent on the condition of the coins.
Silvery coloured Australian coins in general circulation are the 5, 10, 20 and 50 cent coins. Their composition is 75% copper and 25% nickel. There is no silver in any circulating Australian coin.
Australian silver coins (5, 10, 20 and 50 cent) are composed of 75% copper and 25% nickel. There is no silver in any circulating Australian coin.
The Royal Australian Mint (RAM) uses a variety of "fonts" on Australian coins, but the information is confidential so as not to make it any easier for counterfeiters.
Although the Australian one and two cents coins were withdrawn in 1992, they are still considered to be legal tender. Any Australian bank should accept them as a deposit into your account or, exchange them for coins of an equivalent value.
The first exclusively Australian coins were issued for circulation in 1910. Any coins circulated in Australia prior to 1910 were British coins. Occasionally there were coins from other countries suitably restruck for circulation in Australia.
Australia does not produce any Sovereign coins.
I cannot find any reference to an Australian gold coin from any year with an eagle on it. Do you have any further information?
From 1967 onwards, no general circulation Australian coin has contained any silver, or any other precious metal at all. Since 1967, all Australian "silver" coins are made from a 75% copper and 25% nickel alloy.
No. There is no precious metal in any Australian general circulation coin. The Australian One and Two Dollar coins are made from an aluminium-bronze alloy.
If you refer to the Australian One and Two Dollar general circulation coins, there is no gold in them, they are made from 92% copper, 6% aluminium, 2% nickel giving them a gold appearance. There are no precious metals in any Australian general circulation coins. Australian non-circulating gold coins which are released annually for investors and collectors, contain 99.99% gold.