Found these at my very old and very modern site. They are not magnetic. I have not acid tested them because they are so small I didn't want to ruin them. They were very difficult to locate....
you have to click on the pictures and then enlarge to get a good view. Thanks for looking.
Those look like contacts. I don't know the actual name! I do know some are silver,gold, and other metals. If that is what they are. They look machine cut too. Like a stamp. One side will have a curve while the other is sharp on the edge? when laying flat.
Ya. they look like slug scrap from a punch press.
Not guaranteeing that of course with out testing but they should be steel. Should have been pretty nasty if recovered from a saline environment though and they look too smooth for corrosion to have factored.
The scrap we used to melt had lots of oil with it but even that would be defeated in an ocean. Similar appearing discs though.
The pic with dime near the stone discs are seated on shows the common fracture marks from a press.