Recommendations on an Urn for a pet?

So I have had a request to make an urn for a pet. The remains volume should be between a cup and a pint. My religious tradition very rarely cremates human remains, so I've never actually handled or inspected an urn. I imagine that I would need to make a lidded box, although I am unsure how to make the lid. Meaning, just how tight do I make the lid? Is it a disaster if the lid is not super tight, with the "pop" sound when it comes off? I don't have the equipment to make a threaded lid. Do you put a small finial for a handle on the lid? Do people glue the lid shut once they put the remains in? I just don't imagine opening it very often.

Sorry for the almost child-like questions. I just don't have experience with them, and want to plan accordingly.