nebelbon

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

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

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.