A smoking pipe, often called simply pipe, is a device specifically made to smoke tobacco. It comprises a chamber (the bowl) for the tobacco from which a thin hollow stem (shank) emerges, ending in a mouthpiece (the bit). Pipes can range from very simple machine-made briar models to highly prized hand-made artisanal implements made by renowned pipemakers, which are often very expensive collector’s items. Pipe smoking is the oldest known traditional form of tobacco smoking. The bowls of tobacco pipes are commonly made of briar wood, meerschaum, corncob or clay. Less common are other dense-grained woods such as cherry, olive, maple, mesquite, oak, and bog-wood. Minerals such as catlinite and soapstone have also been used. Pipe bowls are sometimes decorated by carving. Unusual, but still noteworthy pipe materials include gourds, as in the famous calabash pipe, and pyrolytic graphite. Metal and glass are uncommon materials for tobacco pipes, but are common for pipes intended for other substances, such as cannabis. The stem needs a long channel of constant position and diameter running through it for a proper draw, although filter pipes have varying diameters and can be successfully smoked even without filters or adapters. Because it is molded rather than carved, clay may make up the entire pipe or just the bowl, but most other materials have stems made separately and detachable. Stems and bits of tobacco pipes are usually made of moldable materials like vulcanite, lucite, Bakelite, and soft plastic. Less common are stems made of reeds, bamboo, or hollowed out pieces of wood. Expensive pipes once had stems made of amber, though this is rare now. Tobaccos for smoking in pipes are often carefully treated and blended to achieve flavour nuances not available in other tobacco products. Many of these are blends using staple ingredients of variously cured Burley and Virginia tobaccos which are enhanced by spice tobaccos, among them many Oriental or Balkan varietals, Latakia (a fire-cured spice tobacco of Syrian origin), Perique (uniquely grown in St. James Parish, Louisiana) which is also an old method of fermentation, or blends of Virginia and Burley tobaccos of African, Indian, or South American origins. Traditionally, many U.S. blends are made of American Burley with sweeteners and flavorings added to create an “aromatic” flavor, whereas “English” blends are based on natural Virginia tobaccos enhanced with Oriental and other natural tobaccos. There is a growing tendency towards “natural” tobaccos which derive their aromas from artful blending with selected spice tobaccos only and careful, often historically-based, curing processes.