Niewmismatic Error Coins

Malaysia Bunga Raya 2005 20 Cents Coin With Off-Metal Errors.
Rarity:RRRR
 Are There Such Things As "Off-Metal" Coins?
They are among the most desired and coveted of Mint Errors.
When a planchet is struck by a pair of dies that do not correspond to the denomination intended for the planchet, an Off-Metal coin or Wrong Planchet error occurs
Off-Metal or Off-Planchet coins are inevitable consequence of the same coin press being used to strike several denominations of Malaysia coins, as well as foreign coins. At the end of a minting run, an employee makes a cursory inspection of the hopper to see if any unstruck planchets remain. Occasionally one is overlooked. If the press is then switched to the minting of a different denomination, the result will be an Off-Metal coin, that is a cent struck on a 5 cents planchet, 10 cents struck on a 1 cent or 5 cents planchet, 20 cents struck on a 10 cents,1 cent or 5 cents planchet,etc.

An even more dramatic wrong planchet error is a coin struck on a previously struck coin of a different metal.