Colophony (also called rosin) is the non-volatile component of resin obtained from conifers, especially pines. Cleaned and freed from water and essential oils, it is a brittle, brownish or yellowish substance. Note that rosin is a specific type of resin. Not all resins are rosins.
Colophonium has various applications, including:
- treatment of the bow of a string instrument
- use as flux (metallurgy) for soldering: The tin-lead solder commonly used for electronics has about 1% colophium as core which acts as flux agent, i. e. it facilitates getting a well conducting non-oxidized connection.
- as ingredient in printing inks, varnishes, glues and chewing gum
- in former times, as medicine
- in sports:
- as main ingredient of a powder used to polish glass when making optical instruments such as lenses (Also, amateur telescope makers use a polishing lap made from rosin to polish and figure telescope mirrors and lenses.)
Colophony also is the name of a Ionic city, from which the resin got its name.
The city was (not is) Colophon. In most of the English-speaking world we use the word rosin. Yo, babe, toss me some Colophony slash Colophonium slash colophium so's I kin colophinize my fiddle bow... Caltrop