Humans value them for their chemical constituents and uses. They are used in varnishes, adhesives, as raw materials for organic synthesis, or for incense and perfume. Fossilized resins are the source of amber. The term is also used for synthetic substances with similar properties.
Rosin, (also called 'colophony' or 'Greek pitch') is a solid form of resin. It is got from pines and some other plants, mostly conifers. Heating fresh liquid resin vaporizes light volatiles like terpenes.
Rosin has hundreds of uses, of which only a few can be mentioned here. These uses fall into groups, such as:
- Resisting slippages (increasing friction): used on stringed instruments, dancers' shoes, in gymnastics, in rock climbing, and on hands of various types of games players.
- In manufacturing soap, inks, some paints, paper, varnish, glue, soldering fluxes, and sealing wax.
- Pharmaceutical products: tablet film and enteric coating, microcapsules and nanoparticles.
- Copal and amber are natural rosins: the lighter components of tree resin evaporated and left a hardened rosin.