Australian 2006, 1988 He $2 Coin Errors Please Help

Well in saying that 5 cent head of queen
Isn't the same size I actually measured the
Queens head on both with an online ruler and both
Are exactly same size.

Having read the linked thread I think it is poorly worded. If it was a genuine $2/5c mule, the size of the queens head on the supposed mule would be exactly the same size as the head on a 5c piece. It is not thus ruling out the possibility of a mule.

Thanks guys all good, I was going through some Australian 5 cent rolls and found something of interest not sure if it has been found already but interesting none the less., I will
Post up shortly.

The 1988 $2 has some sort of mark on the coin - the accepted cause is a scrape from a rolling machine.

1. Correcting the terminoloy in the OP's pictures. "Planchet" (with only one "t") is the name given to the blank, the round blank piece of metal the raw material that a coin is made from, after it has been put through a milling machine to give it a raised rim. A "mule" doesn't use the wrong planchet. A "mule" uses a wrong die.

2.

All sorts of things could make a cupronickel coin look gold-coloured.
- Environmental damage, specifically burying the coin in the ground, can make a cupronickel coin turn brownish colour. Sitting in a chlorinated pool or fountain can also impart a brownish-yellow colour.
- Somebody could have plated it. Electroplating or simple chemical plating with a yellowish metal, even with gold, doesn't cost that much. To answer "why", you'd have to ask the people doing it. It's not as common to find plated coins here as it is in America, where mail order mass-marketing companies sell home-plated versions of common circulated coins for hugely inflated prices. Of course, deliberately plating or painting a 5 cent piece to try to make it look like a $2 coin (or plating a 10 cent piece to try to make it look like a $1) is a criminal offence; it's considered "counterfeiting".
- It could, conceivably, be a "wrong planchet" error, where a blank intended for a brass-coloured foreign coin accidentally gets used. The Royal Australian Mint no longer makes its own blanks, but sources its blanks in bulk from South Korea, so it's possible the Koreans accidentally put a wrong blank in the barrel before shipping it, and the RAM never noticed the wrong blank as it was fed into their production line. It's really rather rare for this to happen (both the Koreans and the RAM have qualiy control in place to try and prevent this), so this is the least likely explanation.

Easiest way to tell the difference is by weight. Get yourself one of those two-decimal-place portable balances. Weigh a bunch of normal 5 cent coins (to check the balance is properly calibrated), then weigh the odd-coloured 5 cents. If it weighs pretty much the same as a normal 5 cents, then it's environmental damage or plated. If it weighs significantly more or less, then it's possible it's a wrong planchet.

to the Community, Really u FW!