Found - Womens Engagement ring

[Winsor_Pilates]

The person will likely go back to Costco and ask if anyone found it.
I'd let Costco membership know and have them contact you if anyone comes looking for a lost ring.

[octothorp]

Originally Posted by Bagor

Why would the cops destroy it after a year?

Because one of those rings out there is going to be the Dark Lord's. Better safe than sorry.

[TheFlamesVan]

Originally Posted by flamesfever

It could be and older woman who doesn't use social media. Perhaps put a notice in the Herald.

With zero friends or family who have social media? I would have to assume at least one person it is mentioned to says "we should use social media to find it!"

[Travis Munroe]

Originally Posted by Kjesse

Some diamonds have micro sized serial numbers and can be traced.

This would be the easiest solution as there is a database and if the ring has a serial number etched in, you will find the owner right away. Take it to any jewelry store and they should be able to check for you.