Editorial What is the relationship between jewels and watch engines? Do the jewels really indicate the value of the watch?

For a long time, watch brands have enticed consumers with the appeal of valuable jewels in their movements. In the past, some manufacturers even went as far as displaying the number of jewels on the dial as a sign of prestige, although this practice has now largely disappeared. However, the question remains whether the number of jewels in a watch movement truly reflects its value, or if this is simply a myth, Here is the answer in this article.

After speaking to experienced watchmakers, explaining the importance of jewels in watch movements was a much discussed topic in the past. Many anecdotes circulate about customers suspecting jewelers of stealing gems from their watches. Although some consumers believe that the use of gems adds to the value of a watch, the truth is that watch jewelry has little economic value. However, jewels play an important role in watch movements due to friction. Friction is a major threat to the proper functioning of a watch movement.

When producing pivots for watch train wheels and balance staffs, there is typically a tolerance of 5 microns above or below the exact number. This means that the precision required for a watch movement is incredibly high, and any friction can have a negative impact on its performance. To prevent this, watchmakers use bearing jewels to house these components, rather than having them rub against metal, which reduces friction and improves the watch's accuracy.

In the world of watchmaking, synthetic jewels are commonly used as bearing jewels, with synthetic ruby being the most popular. These jewels are grown in a controlled environment and are known as "boules," a French word for cone-shaped chunks of material. After growth, the ruby jewels are then shaped through a difficult and time-consuming process that involves milling, sawing, and polishing using diamond-tipped tools. Unlike natural rubies, synthetic rubies do not have inclusions, which makes them easier to work with as bearing jewels. Synthetic rubies have a minimal grain and can be polished to a very high standard, making them an excellent choice for watchmaking. On the Mohs scale of hardness, both synthetic and natural rubies rate at 9, while diamond, the hardest material on the scale, comes in at a rating of 10. As such, synthetic rubies are a practical and cost-effective choice for use as bearing jewels in watches.

Modern-day watch jewels are typically friction-fit into the main plates and bridges, a process that was first introduced in the 1930s. Prior to this, jewels were "rubbed in" to a brass setting, making replacement a more laborious task.

Contemporary watches incorporate jewels in a variety of areas, including as pivot bearings for wheels, automatic winding components, and calendar mechanisms, as well as pallet stones. In a watch, the gear train wheels are responsible for transmitting power from the mainspring to the escapement. To ensure this process is as efficient and friction-free as possible, jewels are utilized as bearings for the pivots of those wheels. The use of steel or brass bearings would result in excessive friction, ultimately draining power from the mainspring. However, the use of jewels, combined with the highly polished steel of the pivots, significantly reduces friction, enhancing the overall performance of the watch movement.

Modern-day watch jewels are typically friction-fit into the main plates and bridges, a process that was first introduced in the 1930s. Prior to this, jewels were "rubbed in" to a brass setting, making replacement a more laborious task.

Contemporary watches incorporate jewels in a variety of areas, including as pivot bearings for wheels, automatic winding components, and calendar mechanisms, as well as pallet stones. In a watch, the gear train wheels are responsible for transmitting power from the mainspring to the escapement. To ensure this process is as efficient and friction-free as possible, jewels are utilized as bearings for the pivots of those wheels. The use of steel or brass bearings would result in excessive friction, ultimately draining power from the mainspring. However, the use of jewels, combined with the highly polished steel of the pivots, significantly reduces friction, enhancing the overall performance of the watch movement.

Movements also use jewels in other areas, such as in the calendar work. For example, Rolex's calibers use a jewel to reduce friction when a lever actuates against a steel cam, ensuring precise date change at midnight. The jewel is mounted on the lever, resulting in a smooth and accurate date change.

Ruby jewels are also used for the roller jewel, positioned on the underside of the balance wheel, engaging with the pallet to release energy. The roller jewel is combined with highly polished steel of the pallet fork, minimizing friction for peak performance.

The automatic rotor is another area where friction consumes power, decreasing winding efficiency. While some movements use ball bearings to increase efficiency, calibers that use an axle rely on jewels. The axle is typically seated against two jewels fitted into the upper and lower bridges of the automatic work.

In addition to the previous applications for jewels, the lug has other uses in complex watch movements, including chronographs, minute repeaters, and countdown timers. Despite this size of the business, it appears that small, precious crafts are of high value.