Over the past 20 - 25 years quite a few of these items have been manufactured that uses a metal base and a glass topping. They usually have an "aged" look, even tho they are not really aged (as one like myself and some others on this site would consider).
They are usually just for pretty/display purposes or for a dry food (like candy/bonbons) because of the bolt in the center. Unfortunately, if it is one that was made in an earlier time, the glass isn't always food safe.