Then I threw them in the magnetic tumbler (as usual.) This is where "the usual" ends. The first two pieces were in the tumbler about ten minutes before I tossed in the other three pieces. Five minutes later I took out the first two pieces....... all shiny and silver. Twenty minutes later I took out the other three pieces and saw something I've never seen before. And, for which I have no explanation.
The top left piece came out looking like a piece of copper. The top right piece is a combination of dark copper, magenta and blue. The left bottom piece is a light gold color and the right bottom piece is the typical silver color (as was the other piece that went in first.)
Most of the pieces are the colors I would expect after dipping them in Liver of Sulfur (not after taking them out of the tumbler.) Somehow my shot has been contaminated but it is so strange that two of the five pieces in the same tumble batch are okay.
So now I have to clean my tumbler with flat coca-cola and try it again. I plan on re-firing the pieces to remove the coloring as they did not polish up well at all. (Obviously they won't be ready for this weekend's sale.)
This is a mystery to me and one I hope to solve.