50 pence coin with a mark

[nebelbon]

I have got a 50p coin from 2005. In the 7th point on the coin (clockwise) there is a bronze coloured mark running across the coin between the 3rd and 4th point on the coin. I was just wondering if this is common and what has happened.

[nebelbon]

To add- the bronze mark is a perfectly symmetrical through the coin and it only shows on the head of the coin.

[Peckris]

To add- the bronze mark is a perfectly symmetrical through the coin and it only shows on the head of the coin.

A picture / scan would be more than welcome

[nebelbon]

Here is a scan of the coin, the line looks darker in real life than it does in the scan.

[Peckris]

Here is a scan of the coin, the line looks darker in real life than it does in the scan.

To my eye it looks like a stain, or alternatively the coppery toning you quite often get on cupro-nickel. CuNi of 1947-1951 is particularly prone to copper streaking.