Why Do Watches Have Jewels? The Surprising Role of Rubies in Mechanical Movements
High-quality mechanical watches often boast about their "17-jewel movement" or "21-jewel mechanism," but what do these jewels actually do? Contrary to what you might think, they're not for decoration—they serve a crucial engineering purpose that makes precision timekeeping possible.
1. The Functional Purpose of Watch Jewels
Watch jewels (typically synthetic rubies) are tiny, hard bearings that:
✔ Reduce friction between moving metal parts
✔ Minimize wear on critical components
✔ Improve longevity by preventing metal-on-metal contact
✔ Enhance accuracy by maintaining consistent power flow
Without these jewels, a mechanical movement would wear out much faster and lose accuracy quickly.
2. Where Are These Jewels Used?
Jewels are strategically placed at high-friction points:
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Balance wheel pivots (most important)
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Escapement mechanism
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Gear train bearings
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Automatic winding rotors (in self-winding watches)
A basic manual-wind watch needs at least 7 jewels, while complex automatics may use 25+.
3. Why Rubies?
Synthetic rubies are used because they:
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Are extremely hard (9 on Mohs scale, just below diamonds)
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Can be precisely shaped and polished
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Resist heat and corrosion
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Are affordable to produce synthetically
4. Do More Jewels Mean a Better Watch?
Not necessarily! While more jewels can indicate higher quality, there's a limit:
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7-17 jewels: Covers all essential friction points
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21-25+ jewels: Added for non-critical functions (calendar mechanisms, etc.)
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"Jewel Inflation": Some brands add unnecessary jewels just for marketing
A well-designed movement with 17 jewels often performs just as well as one with more.
5. Modern Advancements & Alternatives
While jewels remain standard in mechanical watches, some innovations have emerged:
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Ceramic bearings in some high-end movements
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Advanced lubricants that reduce jewel dependency
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Silicon components that resist wear
Brands like Wishdoit watches use jeweled movements effectively, balancing traditional engineering with modern reliability.
The Bottom Line
Next time you see "jewels" listed in a watch's specs, remember—they're not there to look pretty. These tiny rubies are the unsung heroes that keep your mechanical watch running smoothly for decades.
Did you know about this function of watch jewels before? Share your thoughts below! ⌚
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