GUM ROSIN

Rosin, also called colophony or Greek pitch (Latin: pix græca), is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature rosin is brittle, but it melts at stove-top temperature. It chiefly consists of various resin acids, especially abietic acid. The term "colophony" comes from colophonia resina, Latin for "resin from Colophon," an ancient Ionic city.

It becomes sticky when warm and has a faint pinelike odour. Gum rosin consists of the residue obtained upon distillation of the oleoresin (a natural fluid) from pine trees (the volatile component is spirit of turpentine); wood rosin, obtained by solvent extraction of the stumps, is usually of a darker colour.