How long does alloy jewelry last?

All metals in jewelry are alloys, they will last longer than you
will live, your children will live, your grandchildren will live.
They will likely last thousands of years, unless seriously
mistreated.

Some jewelry alloys tarnish but they can be cleaned and look good
as new.

Where is trump jewelry manufactured?

China. In fact, the vast majority of the products and merchandise manufactured under the name of Donald Trump and others in his family were made overseas. For example, his brand of neckties, shirts and suits are made in either China or Bangladesh. Some products have also been made in Honduras, and most accessories were made in China, or just say “imported.”