Gold is the most famous precious metal. It is mainly used in watchmaking to make watch cases and sometimes also watch straps. Due to its high density, gold is also sometimes used to make oscillating weights. Gold is used in different proportions in its alloys. This proportion is expressed in carats, which are actually 24th or thousandths. The main alloy used is 18 carat or 750, also sometimes 14 carat or 21, 22 and with rare exceptions 24 carat.
Gold was used very early, many centuries ago. The reason for this early use is that it is a metal which, like copper for example, is found in its native state. That is to say, in the form of nuggets without having to extract it from ore for example. For a few decades in the 20th century, the gold used in the United States for watches and jewelry was mainly 14-karat gold, also called American gold. Sometimes, some countries also had specific laws regarding the hallmarking of gold. For example, during a certain period, Portugal required that the hallmark be visible on the dial side of the watch. This is how the life of a watch can sometimes be traced.
In watchmaking, gold is mainly used for the watch case and bracelet. It is also sometimes used for rotors and micro-rotors, and sometimes segments of these, on automatic movements. It is quite common to have gold hands and/or indexes on high-end watches. Gold can also be used as a decorative layer ranging from gold flash to thicker gold plating. Parts such as brass or nickel silver plates or bridges are sometimes gilded. Some houses also make gold plates and bridges.
Gold has the advantage of being stainless, which makes it a sought-after component for dressing. Moreover, historically gold has always had a role of excellence and rarity, associated with luxury it represents an important asset for a collection. The fact that gold can move in different colors allows a wide variety of colors for a model.
Gold has the disadvantage of being heavy. It is also sensitive to expansion under heat. Secondly, gold is soft and therefore can be complicated to machine, which is why it is almost never used in 24 carats but rather in 18 carats, which somewhat neutralizes its defects. If too pure, it can be sensitive to damage (shocks, scratches). The extraction of gold can be harmful to the environment depending on how it is done.