What’s the deal with jewels in watches and are they worth anything?
Well for starters, if a watchmaker is talking to you and mentioning the jewels in your timepiece, they actually talking about jewels that are found within the watch mechanism itself and not decorative pieces on the case. Its purpose is to reduce friction build-up and helps to provide a smooth long lasting surface bearing at several points within the timepiece, therefore increasing the watch’s running efficiency. Most jewels are made from sulphates of ammonia and aluminium which are exposed to chemical, thermal and mechanical processes to turn them into these dark red ruby lookalike items known as a “boule”. After that, the jewel is exposed to several other processes to transform it into a polished item.
Here are some of the types of jewels you might find in your watch: (these images are greatly enlarged!)
These little pieces which are always found in pairs are used to cover the hole of the jewel and prevent sideways movement of the jewel by allowing the wheel pivot to ride on the cap. This is particularly useful to prevent contamination of the jewel and pivot as well as to reduce friction even further.
This jewel is a type of angle faced jewel which is attached to a pallet fork and interacts with the escape wheel and teeth. You will find two types known as entry and exit pallet jewels within a watch. They work in synergy to take turns to lock the gear train and transfer impulse power through the jewel to the balance. This can occur approximately fives times per second on an 18 000 BPH watch.
The last type of jewel is known as the garnet “pin” or ruby jewel and normally comes in a D type shape. The average watch has one of these located on the roller table of the balance. The impulse jewel will oscillate back and forth as the balance turns and will contact the pallet fork on every swing. This helps to unlock the pallet which in return lets the wheel escape to advance to one tooth, therefore regulating the watch escapement. In vintage watches, this jewel is kept in place with a melted shellac.
Photo Credit: Reddit
Do Jewels determine the Value of the Watch?
As a rule of thumb, the more jewels that are found to be in a watch, the higher the quality of the watch. It also can be said that a highly jewelled watch could have a mechanism that works better than if it had only a few jewels, however, many factors can affect the functioning of a watch.
Watches made before the 1970’s typically used 5 or 7 jewels, but that has now been taken over by quartz. These days, your average manual watch will have 17 jewels which are:
1- Impulse jewel
2-5 Balance staff pivot bearings
6-7 Escape lever pallets
8-9 Escape lever pivot bearings
10-11 Escape wheel pivot bearings
12-13 Fouth wheel pivot bearings
14-15 Third wheel pivot bearings
16-17 Center wheel pivot bearings
A higher number of jewels does not always guarantee a higher-quality watch, but rather a correlation between higher-quality watches and more highly-jewel watches. Should you buy a watch with jewels, its best to stick to one with 15 jewels and more.