Quote Originally Posted by charlie b View Post
I thought they used jewels/stones. Ruby, agate, etc.
You may be thinking of Jeweled movement/bearings. Often found on things like indicators and watches. Interesting thought. The load might be a bit high for something like that. I always wondered what a high precision, small ball, frictionless bearing mounted to self align would do. The engineers seem to like the knife edges though so there must be a reason.