Coinsandcanada.com

Hi. I bought this dollar piece written yellow teinted and it was in special. By looking at it i'm pretty sure that is gold plated because of the brightness and lack of other color in the discoloration. Did RCM did some mistake or is it the doing of a previous owner? How to know what cause this bright yellow gold color on the entire coin?

Welcome to the forum.

That was gold plated by a third party after it left the mint.
To a collector, that would be considered an altered coin.

During this time period the RCM has admitted to using a rinse that caused some of their NCLT coins to turn a goldish colour, there was a story and confirmation by RCM spokesperson in Canadian Coin News a little while ago.

If the coin was stored in a wood box, especially oak, it could also turn colour., especially because of the mint coating. The plastic holder isn't air tight. I wrote about this talking about a squirrel coin the mint put out in this forum too.