In 1960 we attained the domestic manufacture for Watch Jewels for the first time in Japan. Watch Jewels are mainly made from Ruby Material. The Ruby is hard to grind and has a highly wear resistance. However, the Ruby Chips grind easily because it is a single crystal. The grinding and polishing of Ruby was very difficult.
Artificial Rubies are also used for Watch Jewels. The inscription of "17 J" or "17 Jewel" on a watch dial is an indication of the jewel number in the watch.
The Artificial Ruby can be made to be very smooth and therefore, allow the metal parts to slide more easily. In addition, they are hard and therefore, do not wear down quickly. The Ruby reduces the revolving wheel friction and the detritions. The Cap Jewels are dome like in shape stones that are placed on the ends of the Wheel Arbors.
