very cool
that's what I'd say, or with the dirt on them part of the sheen could be from what happens to marbles underground
but now I better step back and let someone else weigh in
P.s., now I see/re-see the box lid which says "reflector marbles". I know that some marbles were used for reflectors. But I also see the molded reflector, so that's why I was spending all that time wondering about whether the Automatic Devices Co. was receiving marbles or molded version. Why not both ...