Assess Jewelry

My teenagers and I recently inherited a bunch of rings and other jewelry that we'd like to learn more about as we decide what to sell, donate, or keep (and if we sell, how to describe the items accurately). I don't think any of it is really valuable, so we're not looking for extensive appraisals or valuations; we'd just like to know whether the tiny stones in a bracelet are diamonds or cz, for example, or whether the black center of a cocktail ring is plastic or onyx. Obviously we aren't jewelry people so we can't do much ourselves aside from looking for gold or silver hallmarks. Does anyone know of a jeweler or someone else that we could pay by the hour to take a quick look at 30 or so small pieces and just tell us what they're made of?