The bowl is most likely made of olive wood. Glasschaum is a micro-bubbled form of glass bonded with some sort of porous slurry. Presumably this is the 1 millimeter thick bowl lining. According to an alt.smokers.group thread, Ben Leibowitz marketed the Glasschaum pipe in 1941 and then disappeared from view, most likely because glasschaum came from Germany and his supplies dried up with the declaration of war.