Rosin is a natural resin obtained as a vitreous water-insoluble material from pine oleoresin by removal of the volatile oils from tall oil by the removal of its fatty-acid components. It consists primarily of tricyclic monocarboxylic acids having the general empirical formula C20H30O2, with small quantities of compounds saponifiable with a boiling alcoholic solution of potassium or sodium hydroxide and some unsaponifiable matter. The three general classifications of rosin in commerce are: (1) gum rosin, obtained from the oleoresin collected from living trees; (2) wood rosin, obtained from the oleoresin contained in dead wood, such as stumps and knots; and (3) tall-oil rosin, obtained from tall oil.