It is very important that suitable material be selected for the mouthpiece of the pipe. In fact from many points of view the mouthpiece is the most important part of the pipe for the smoker, because damage to the lips must be particularly avoided, and a defective, rough, or badly made mouthpiece is apt to cause damage. There are three very important qualities which the material must have: (1) It must be hard enough to resist indentation from the teeth and yet not feel gritty. (2) It must be capable of receiving a perfectly smooth surface and of retaining it under the action of saliva. (3) It must not be a rapid heater so that it will not burn the lips, or crack or splinter under action of heat. Other very desirable qualities are toughness, beauty of appearance and freedom from taste or odor under all circumstances of use. Amber has a unique place in fulfilling these conditions. Amber is a fossil gum or resin, the juice of pine trees, which in course of time has become petrified like coal. Amber is found is various parts of the world, but is more plentifully found along the sandy shores of East Prussia bordering on the Baltic Sea. This area was in time long past the site of pine forests. The amber is found very often to occur with lignite or brown coal. It is dug out of the cliffs or mined like coal out of the ground. Sometimes it is washed in from the sea. In size it varies from the size of a pea to lumps as large as an orange. When first dug up it is usually of a pale yellow color, but this becomes darker on exposure. The manufacture of commercial amber is a government monopoly in Prussia. The pieces are all melted down at a temperature of about 550° F., and then after purification it is cast into slabs about 7/8 inch to 1-5/8 inches thick and four inches to eight inches long, in which form it is sold to dealers. There are two qualities, opaque and transparent, the opaque being the tougher. The cost varies considerably, the inferior kinds being sold for $2.00 per pound, and the finest specimens cost up to $60.00 per pound. By far the largest quantity of amber used for ordinary pipes is imitation amber. The manufacture of this is a trade secret. It is so good and fulfills its purpose so well that only experts can distinguish it from genuine amber. There are many substitutes for amber. Good vulcanite, except for the matter of appearance is little inferior to amber as mouthpiece material. Cut vulcanite is cool and smooth, but moulded vulcanite is liable to be rough to the lips and should be avoided. Vulcanite mouthpieces are usually sold already finished direct to the pipe makers.