I have a coin (1839 Swiss Canton-Geneva 2 centimes) that's listed in both billion and silver. Is there any way to tell the difference in the two materials short of chemical analysis?

Billon is a silver alloy with under 40% of silver and over 60% copper. So, the billon coins are light red in colour, normally with the free eye you can see the difference. Even under patina of billon coins remain the red colour. It looks like more than a copper coin like a silver one...

Thanks! I'll post some photos here later. The coin that I have appears the same as other old silver coins that have toned...kind of a grey color. I certainly hope that it's the silver issue.

Here are the photos...it has a die crack that I did not notice until I looked at the enlarged photos.

Could be wrong, but it looks like billon to me.

Great design