JEWEL

Precious stone used in movements as a bearing surface. Generally speaking, the steel pivots of wheels in movements turn inside synthetic jewels (mostly rubies) lubricted with a drop of oil. The jewel's hardness reduces wesr to a minimum even over long periods of time (50 to 100 years). The quality of watches is determined mainly by the shape and finishing of jewels rather than by their number (the most refined jewels have rounded holes and walls to greatly reduce the contact between pivot and stone).

JUMPING HOUR
Feature concerning the digital display of time in a window. The indication changes almost instantaneously at every hour.