Jewelry Appraisal?

Jewelry Appraisal?
I’ve heard that when one gets jewelry appraised, one should go in the back with the appraiser or stand there and watch. “It only takes a second to pop out a diamond.”

How is this done? I have never had an appraisal. Does one just say that you have to come back with them, or do they usually offer?

What is the rest of the protocol? You go in the store and ask for an appointment, or do they look at the pieces right then?

I guess it is good to get a free or cheap appraisal at first to assess general value, then if something is worth insuring, one should pay for the indepth and more expensive appraisal.

Any other information would be helpful.