I know they are not made of metal but glass, but the ball bearings are.

Since there are a few that have went prospecting looking for metals & such. How many glass marbles and ball bearings have you found?

I ask as I have found them around my place as well as other older properties when digging about on the top of the ground with rakes and such.

I was told by a older gent that years back when the sling shots were popular that glass marbles and steel ball bearings were the choice of ammo.