Platinum Ring has a black mark - Please help me understand what this is

[UYU35Z]

Hello, I just received my engagement ring today and noticed a black mark on the inside of the rings' shank.

It is made of Platinum Cobalt (Pt950 alloy) and was casted.

Other than aesthetics, is this a defect I should be concerned about? I rather it not be there, but if my future fiancee is wearing it - it won't show anyways. I am more-so concerned whether or not it poses a structural issue or worse.

Thanks in advance for your analysis and comments.

Here's the album link:

https://imgur.com/a/UDeNLRe

 

[Bron357]

It’s probably a spot of tarnish not removed after manufacture. You should be able to remove it with a polishing cloth for Silver. Otherwise return it to the jeweller you purchased it from and ask them to clean it better!

 

[UYU35Z]

It’s probably a spot of tarnish not removed after manufacture. You should be able to remove it with a polishing cloth for Silver. Otherwise return it to the jeweller you purchased it from and ask them to clean it better!

I thought platinum is not supposed to tarnish? And would a microfiber cloth work? or only a polishing cloth would work for this kind of thing if it is indeed tarnish?

Thanks for your response.

 

[Bron357]

Did a bit more reading. It could be a “spot” of other metal that has inadvertently fused to the Platinium while it was worked on. Apparently you have to use Tungsten rather than steel holders / wire as they can transfer onto the Platinium at the high working temperature.

 

[bludiva]

The jeweler who made the ring should be able to buff that out

 

[UYU35Z]

Hi, thanks for responding to my thread Bron357 and bludiva!

Turns out it was a bit of polishing compound left behind, I was able to remove it with ease using a cloth ! Very happy my concern of porosity/pits/etc defects was not an actuality whew*