Valuable Australian Coins You Can Find In Your Change

[Australian coin]

the 85 50c, although people say is a low mintage, I have "we my family" came across a few in change, you prob don't come across them as often as when we first started, and I guess as more people look for them the harder it will get, {supply and demand}
error coins come mainly from production, so with a machine that pumps out a few hundred in a minute, you cant guarantee, that its going to do every coin exactly the same every time, a coin may be flicked in the stamping mechanism the wrong way, the wrong timing, or a die might start to wear out or develop faults - all part of the manufacturing process
then the coin planchet (coin blank) - (before being stamped with the design) itself may have flaw too, like the wrong metal mixture or a air bubble under the surface, when struck would cause a lamination effect, split planchet