A rummer (Römer in German) is a large glass, often with a thick, hollow stem and base, popular in the Rhineland and the Netherlands in the 15th, 16th and 17th centuries. A Berkemeyer is similar, but has a wide, flared bowl and is often made with thicker glass.
Both rummers and Berkemeyers often have a green tint, due to impurities in the sand used to make the glass. Their stems are often studded with small blobs of glass, known as prunts, both for decoration and to provide a safer grip. The prunts are often moulded into decorative shapes such as fruits or lions' heads.
Rummers and Berkemeyers were often depicted in still lifes by the Dutch masters of their period (as shown here on Wikipedia; the one standing upright is a rummer, the one on its side, on the right, is a Berkemeyer).
© Haydn Thompson 2020