Help with ring ID please.

[Rob W. FL]

While putting away a collection of stuff I gathered from the beach over many outtings I ran across this ring.

It looks like Gold although it is a bit on the dull side. Its non-ferrous and has ZZ R .418 ( r is in form of registered trademark)? stamped into it.

Anybody have a clue as to what it may be?

Thanks
Rob

[Lasivian]

.418 means 10 karat gold.

here are all the different weights:

http://www.hooverandstrong.com/mill/castinggrain.htm