What is it & when is it

I have this piece that I haven’t been able to find any info on — what was it used for? How old is it? Who makes it? — I see the markings stamped USA with a coat of arms (?) symbol but cannot find it online.

It looks like a small flower vase, designed to keep shorter stemmed flowers from falling out, etc. Also, it is probably not silver, and from the photos, does not look like silver plate. Possibly it’s pewter? I’m not familiar with those markings, myself.