One of the key questions we get from novice collectors when they read about watches and the technical specifications of the movement is, "Are the rubies inside the watch real?"
In fact, unless a new watch utilizes high-tech ceramic ball bearings in certain parts of a watch movement, all mechanical movements utilize synthetic gemstones as bearings instead of metal bearings that need oiling.
The synthetic gems — typically rubies, but sometimes sapphires — eliminate the need for oiling and significantly reduce friction and wear and tear on the movement parts, enhancing the life of the movement. Sometimes, those rubies are visible via a transparent sapphire caseback, or via a skeleton movement where so much of the metal is pared away to allow viewing of the superb mechanisms.
Rubies have other added benefits to watchmakers, as well. Because they can withstand temperature changes without any reaction (unlike metal bearings) they offer higher stability. Synthetic rubies are generally created using aluminum and chromium oxide that are heated, fused and crystalized. They are not as valuable as genuine rubies, making them more affordable to use. This is especially important because a watch can have anywhere from a few rubies to dozens inside the movement.
Setting these minuscule jewels into their designated spots is no easy feat and watchmakers use microscopes and tweezers to accomplish the job. In the end, the look is beautiful and the purpose is practical.