Figured I would share this question that I get asked alot by new smokers that I know. Is it acrylic, or is it vulcanite? My answer to them is this. Other than the difference of one being harder than the other, there are two tests that I do. First, I tap the stem on my thumb nail. Sharp tap, acrylic. Dull tap, vulcanite/ebonite. Second is smell. Rub your thumb against the stem with enough pressure to make your thumb slightly warm. If there is the smell of hot rubber, vulcanite/ebonite.