Ruby is a precious stone that belongs, like the sapphire, to the group of corundum. It is obviously found in nature but since the beginning of the 20th century it can also be created artificially.

In 1902 Auguste Verneuil invented the Verneuil process which allows the creation of artificial corundum (ruby and sapphire).

Natural rubies are sometimes used in watchmaking to adorn cases. However, they are mostly used in movements to reduce friction at the pivots. Indeed, the friction between the ruby and the polished hardened steel pivots is one of the best frictions. For movements, the rubies used are synthetic because they are free of inclusions that could add friction. The pivoting rubies can also be of different shapes. The more common quality rubies have flat faces and cylindrical holes. The higher quality rubies have domed faces and olive holes to reduce friction and increase the capillary effect of the oil.

The advantages of synthetic rubies in watchmaking are therefore to reduce friction and wear and improve accuracy and power reserve. Natural rubies are used to embellish the beauty of a case and increase its value.

The ruby is a stone that welcomes oils, so it is prone to soiling and it must be meticulous in maintaining movement.