Well, the majority of the ELW-rings are rocky. I remember that I found few metallic rings. But I can't remember icy ones. A quick look at EGO could help, but the site is unfortunately offline for a year or so. They had records for everything...Not yet. Initially a member of the Explorer on Tour, who unfortunately passed away far too early, was looking for a metal rich body with an ice ring. I don't know if that is possible. It's some kind of a holy grail. And then the question occurred whether there are Earth-like planets with ice rings.