Tobacco pipes come in three major types: Briar,
meerschaum and
corncob. All three have different characteristics.
Briar pipes are carved from a part of the briar plant known as the burl, which is a big knot of woody stuff that anchors the plant in the rocky soil of Corsica and Spain. This is very hard wood, so briar pipes are very durable and don't burn. This is the most common kind of pipe, and you can find them carved into a thousand different shapes and stained a hundred colors. The cheapest ones will be of pressed briar, like plywood. These pipes suck, and can clog with moisture or split. More expensive briar pipes are made by such companies as Savinelli, Peterson, Nording, Dunhill, Bari, Kaywoodie or Nat Sherman, and are typically choice core briar. These pipes will shed heat better and can last for decades, as well as usually being beautiful.
Meerschaum pipes are expensive and fragile. They are less common than briar pipes nowadays, but in times of antiquity they were considered the superior man's smoking implement. Meerschaum, German for seafoam, is a white sedimentary stone that forms on seashores, similar in some ways to chalk. It was used to make pipes with because it can shed heat very well and with use acquires a beautiful marbled stain. Most meerschaum now comes from Turkey, and they have some kind of government interventionist export company that I don't understand. Meerschaum pipes are stark white and carved into anything you could name - Gothic scallops, skulls, famous composers, elephants - but I've never seen a stained one. These pipes have no break-in period and impart a cool, dense texture to smoke, but don't drop them!
Corncob pipes are made in Missouri and are perfectly eponymous, just a baked corncob with a hollow stick. Their stems and mouthpieces are the standard vulcanite or plastic. These pipes are disposeable in a way, as they will burn through eventually. Accordingly, they cost a fraction of the other two types. They are uniquely American and are present in our national mythology if you care to look for them. Corncobs impart a sweet, airy taste that marries nicely with most tobaccos and some pipe smokers refuse to part with their corncobs. These also have zero break-in time.