Today’s modern 4 ducat follows in the famous steps of the Austrian 100 Corona and Austrian 1 ducat in that those dated 1915 are re-struck. A re-strike is an official reissuing of a coin which is no longer in production.
The Austrian 1 Ducat is made of gold which is 0.987 pure (high purity) and its melt weight in gold is 0.4431 troy. So a virtually pure gold coin which contains a little less than 1/2 of an ounce of pure gold which is slightly more than 1 ½ inches in diameter.