What is the meaning of olive hole balance jewels? Do they come stuffed with pimintos?

Recently I have broken two crystals while trying to put on hnting case bezels. Is there a technique to prevent this?

An older, simple hole jewel will have a cylindrical hole through it (straight sides) and the pivot will have contact along the full length of the hole. An olive hole jewel has a hole that is beveled (actually rounded) from both sides so that the pivot contact is minimized. The name may come (my inference) from the cross-sectional view of the jewel that might look like two olives.

Breakage of some geneva crystals is almost inevitable if they are a snap fit. It just takes an awful lot of care to put them in. Or use a crystal that is small enough to not snap in and use crystal cement to secure it. If the breakage is occurring when putting the bezel back on, you can put the bezel on first, then install the crystal (and let the next guy worry about it ). In these instances a looser fit crystal might also forgive some slight flexing of the bezel as it is put back on. If the height of the crystal is wrong, of course, the cannon pinion or cover could break it, but I assume you are talking about fitting it to the bezel or installing the bezel.

I am talking about putting the bezel with the crystal mounted back on the watch.

I find that they go on better if I line the hinge side up with that side of the case.If it has a lineup pin on the side I line this up.Then use two fingers to gently push the bezel down on both sides at the same time.
You are going to break one once in a while,so get used to it.
J Smith