Ruby / sapphire industrial jewel (Jewel bearings), jewels and pivots are miniature components used in instruments and controls that require low friction, long life, and non-magnetic properties. They are usually made of sapphire, ruby, or hard glass. Jewel bearings, jewels and pivots exhibit rare combinations of design characteristics. For over a century, jewel bearings, jewels and pivots have been used as reliable, low-friction devices to keep watches and timepieces working accurately. Cup bearings are jewel bearings that fit a ball bearing between two-cup jewels or semi-spherical pivots. Cup bearings are often used in vertical shaft applications, such as compasses and heat monitors.