I read about the watch movement (watch "engine" for the laymans) decoration and would like to share the followings :
There are different types of finish or decorations that is found on the watch movement. (Accompanying pictures extracted from ETA, the movement maker)
1) The Vrac - it is the electroplating of the movement to provide some form of protection rather as a finish or decoration. The movement is plated with either nickel (cheapest), gold) or Rhodium (the most expensive).
2) Flat matte finish - as the name implies, this finish is matte and looks unfinished and is the most basic of finish available in most watch movements.
3) Flat Brush Finish - this finish is achieved by brushing the finish is a single direction. (Not sure if it is the same as Adoucie)
4) Adoucie - a form of polishing that is either linear or circular and was achieved with the use of abrasive paper.
5) Colimaçonnée - or Colimaçon (snalling or spiralling); like its namesake, snalling is a decorative finish which takes the form of curved lines orginating from a common center, much like a snail's shell.