UNCAS Brutalist Style Ring - Material ID & Dating Help

Hello,
This is an Uncas ring, marked with a U with an arrow through it. Next to the Uncas mark is the number 10. It does not include any letters after it. The metal is a bright shiny silver tone; the stone is cubic zirconia.

Is this 10K gold plated or gold filled?
What decade do you think it's from?

Thank you!

 

I think 10 is likely the size

I doubt there is any gold there

 

Seconded. Uncas did make some sterling, but this is a recent piece. Odds are it's straight-up costume.

 

Thanks!