This is an incredible set of what seems to be lava but is actually stone. What kind I don't know but there seems to be 5 different types of stone. Could have been carved in the late 1700s or very early 1800s. Each is about the size of a half dollar and is mounted on what seems to be the original case or mounting. Apparantely from some collection. (This piece was purchased from an estate in Argentina and not italy) A true collectors item.