Gum Rossin, also known as colophony or rosin is a natural organic resin that is obtained from plants, mostly pines and other conifers, when the fresh liquid resin obtained from these plants, is heated and the volatile liquid terpene components are vaporized. It is used only in making High tensile reclaim rubber.

Gum Rossin is used in making High Tensile Reclaim Rubber. It increases the Tensile Strength of Reclaim Rubber and gives elasticity to Reclaim.

It is solid and vitreous, brittle at room temperature, melts at higher temperatures , is insoluble in water and soluble in organic solvents. It also has a faint piney odour.