Gum Rosin acids are the complex mixture of several compounds, particularly abietic acid types and the pimaric acid types which belong to the diterpene group of organic compounds. Abietic acid has conjugated double links and carboxyl groups. Pimaric acid is the dehydro form of abietic acid. Oxidation of abietic acid makes colophony more brittle and darker. The carboxyl group and double links in the acids can yield many kinds of salts and modified compounds for better purposes.

Gum Rosin and modified forms (salts and esters) are used in making papers, varnishes, paints, adhesives, and some soaps. Modified products with turmeric and malefic acids (or anhydrides) are used in manufacturing alkyds. Other uses include sizing for paper products, paint dryers, plasticizer in rubber, waterproofing, emulsified oils, dressings for machine belting, enamels used in ceramic manufacture, roofing cement, sealing wax, linoleum, oil cloth, lutes ointments, plasters, veterinary medicines, disinfecting compounds, dry batteries and electrical insulation, production of fungicides, antislip agents for floors and shoes, violin bows.

The water solubility is negligible. But rosin is soluble in alcohol, ether, turpentine, and some organic solvents. It dissolves various metal hydroxides. Rosin is a complex derived from wood, especially pine wood. Composed primarily of resin acids and modified resin acids such as dimmers and decarboxylated acids.