rosinin

Rosin, also known as colophony or Greek pitch, is a solid form of resin obtained from the sap of live coniferous trees, most notably pines. It is typically produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. The remaining material is a brittle, amorphous solid, usually yellowish to amber in color.

Rosin is soluble in many organic solvents, including alcohol, ether, benzene, and chloroform. Its primary uses are related to its sticky and abrasive properties. It is widely used by string players of musical instruments, such as violinists and cellists, to coat the bows, which increases friction between the bow hair and the strings, allowing for sound production. In industry, rosin is a component in printing inks, varnishes, adhesives, and soldering fluxes. It can also be used as a glazing agent in some food products and as a component in chewing gum.

Historically, rosin had numerous applications, including as a waterproofing agent for ropes and sails and as a component in torches. It has also been used medicinally, although its efficacy and safety for such purposes are debated. Sensitive individuals may develop allergic contact dermatitis from exposure to rosin, particularly in occupational settings.