The Quartz Revolution made quartz ubiquitous in the watch world, but your automatic watch has its own hidden gems. The careful placement of tiny sapphires or rubies maintains timekeeping accuracy and supports centuries of longevity.
Virtually every mechanical watch contains a stash of jewels secreted within the case. These gemstones serve as bearings for the metal pivots of the movement’s gears, wheels, and pinions.
In the early days of watchmaking, movements were crafted entirely of metal. Some of the gear-train elements—and therefore, their bearings—didn’t exist exactly as we know them today, but these watches weren’t particularly accurate and didn’t last very long, either. The friction between their moving parts caused variations in timekeeping, plus premature wear and corrosion to the components.
Jeweled Movements Stay Smooth
Watchmaking’s first 200 years or so were primarily about novelty, though. Rich people wore clocks as pendants or carried them as trinkets. No one necessarily expected that they would measure time beyond an approximation of hours.
Swiss inventor Nicolas Fatio de Duillier changed that in 1704, with the help of brothers Peter and Jacob Debaufre, when they developed jewel bearings. Crafted of natural diamonds and corundum—you might know red corundum as ruby and any other color as sapphire—these new bearings were slick, strong, durable, and produced remarkably low friction.
Timekeeping still wasn’t foolproof, but the minute hand was becoming more commonplace around this time, too, so watch enthusiasts were beginning to notice accuracy more than before.
A variety of macro-factors kept watches in the realm of the affluent for at least another century, but the expense of natural gemstones certainly played its part.
Corundum is so strong that diamond abrasives were required to hone their silhouettes, too, adding to the cost.
Today’s automatic watch movements feature synthetic sapphires and rubies.
Synthetic corundum, by the way, is indistinguishable from the naturally occurring kind. Plus, lasers cut these jewel bearings.
ROCK AROUND THE CLOCK
These self-winding watches are called “fully jeweled,” which means they contain 17 jewel bearings from the balance wheel to the center wheel pivot. They feature an additional 4 jeweled capstones at the lever and escape wheel bearings, plus 4 more jewels at the mainspring barrel and self-winding wheels for a grand total of 25.
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