If it is jewelry processing, I will let you have a try. See how your skills are.
If it is an appraisal, you need to know something about jewelry, and you may also be shown something like diamonds.
If it is sales, you should examine your eloquence, business etiquette and professional knowledge.
If you are applying for jewelry design, you should bring your own design works, otherwise you may be asked to draw on the spot.
In fact, interviewing jewelry companies is the same as other industries to see if you have relevant experience.