Would you like ground glass with that?

This morning I was making Carl's daily smoothie breakfast when I noticed the smoothie coming out of the BOTTOM of the blender jar! I immediately turned the switch off; Carl came to help; and we poured the half-blended smoothie into a jar. Carl pulled out his tools, did whatever fix-it people do, and said I could carry on with smoothie-making. So I finished blending his smoothie, poured it into a glass, and started working on making my smoothie. Before I got too far, Carl said, "Linda, there is something gritty in this. Do you know what it could be?" I said, "It's milk, chocolate protein mix, bananas and blueberries -- I have no clue." So we decided I'd make mine and, if it was gritty he could continue drinking his; if it wasn't he would stop. Same thing happened: smoothie-makin's started coming out of the bottom of the blender jar! Carl took the blender-bottom apart again and we discovered the blade had become loose and had ground away some of the glass surrounding the drive shaft! So the grit in Carl's smoothie was, in fact, ground glass!