An item generally round in shape and usually having a centrally located hole. It has at least one flat bearing surface. It is made of precious or semi-precious gem (ruby, sapphire and the like), natural or synthetic. It is intended for use in precision instruments, meters, timing devices, clocks, and the like.
to 5n11-2-11-33 reference data and literature, jewel part name assigned by controlling agency, used with screws 20000740, 20000687, and plate assy 400193 special features, aircraft mechanical clock 6645-00-076-3050 end item identification