What is going on with this coin's color, 1934, Austrian 2-Groschen

[Prosit]

The Austrian 2-Groschens in this series were minted in 1925, 26, 27, 28, 29, 30, 34, 35, 36, 37 and 1938.  I have the entire date run.  All the coins are the same color as the coin on the left except for my 1934 example (on the right).  It looks Silvery/Nickelish color and I don't think it should.  It isn't uncirculated and no different color shows through the lite wear it has.  I know coins can be colored but 1934 is the rarest of the series at 812k mintage.  This coin normally should sell for between $15-30 USD.  Why would someone color that coin?  I don't have a scale to see if there is a difference in weight.  Might be a different metal....not very likely but remotely possible.

Anyone care to offer an opinion or speculation about what may have, might have, could have happened here?

Dale

[Austrokiwi]

The only Groschen coin I have is a 38 5 Groschen.   Are the 2 & 5 groschens the same diameter?  if so perhaps you have a 2 groschen struck on a 5 groschen planchet.

[andyg]

2 Groschen 20mm ~ 5 Groschen 18mm.

Could be an off metal strike?
More likely though is that it's discoloured for some reason.

[Arminius]

Looks like stripped and repatinated by those repatination liquids.

These contain sulfur conpounds and the metal is covered by dark-brown to black copper sulfides.
The copper (I) oxides show those red to brown colours.

regards

[Prosit]

Ahh but the coin I am asking about is the one on the right which is the color of a US Nickel. (Silver color) The one on the left is the normal color of these coins.  I did increase the image contrast and darken them a bit to remove the dullness I get from my scanner.  The one on the right may be cleaned but the one on the left hasn't been, at least not in recent history.

Dale

Looks like stripped and repatinated by those repatination liquids.

These contain sulfur conpounds and the metal is covered by dark-brown to black copper sulfides.
The copper (I) oxides show those red to brown colours.

regards

[Figleaf]

Have you compared the weight of the odd coin with that of the normal coins?

Peter

[Prosit]

No, I don't have an easy way to do that.  I have no scale.  I think I definitely should get that done though.
Dale

Have you compared the weight of the odd coin with that of the normal coins?

Peter

[Figleaf]

A friendly jeweller might help (don't tell me the nearest one is in Austin).

Peter