What is this mark on gold coin?

[ram64]

Hi everyone,

Interested in purchasing a 50 Pesos coin from someone, but it has a black mark across it. Does anyone know what this mark could be? Done a few standard tests (weight, size, ping sound etc) on the coin and it seems authentic, but that black mark doesn't go away with water, 99% alcohol or usual water, aluminium foil  & salt, by what I've been told. Is this an acid mark and is there any way to safely remove it or at least fade it?

Best regards,

Alex

 

[Draconicus]

I don't have a clue about what have made it, but try a pencil rubber... maybe it works.

[augur]

Could be a planchet flaw where two strands of metal were cold fused. Never seen it so boldly expressed, though.

I don’t think you can fade it without damaging the coin. 

[augur]

Looking closer at it there is also some delamination at the rim near ESTADOS so most likely the metal of the planchet was flawed in several ways. 

But then there are some people who embrace flaws since they were less common in those days

[ram64]

13 minutes ago, Draconicus said:

I don't have a clue about what have made it, but try a pencil rubber... maybe it works.

Thanks, already tried that as well (forgot to mention it).

1 minute ago, augur said:

Looking closer at it there is also some delamination at the rim near ESTADOS so most likely the metal of the planchet was flawed in several ways. 

But then there are some people who embrace flaws since they were less common in those days

The mark is just the one across the coin. On the rim those are just reflections due to my poor photography skills

Thank you both for your input.