Here is a gem from my collection I bought many years ago. I don't take it out to often because I am afraid of losing silver. I decided to try to reshoot it today. Not a great coin except the amount of silver , when I bought it I was told the story of two dealers in dispute over the coins ( It was part of a found hoard.) being electrum or not, they sent the group to David Sear and he stated they were Billion but with a very high content of silver. Here is my example from that group. I have also included another example I own to demonstrate the difference.
This Alexius I (1081-1118) really is this silvery, which is remarkable for a late billon aspron trachy. 26-24 mm. 4.28 grams. Sear 1918 DO IV.II 25 "struck 1093-1118"
The silver content for these coins were at 6 to 7% at their best , by the time of Alexius III it was down to 2-3%
Perhaps something like the antoninianus coins of Aurelian or Probus that started out with a silvery coating that quickly wore off it circulation.
Yes, the silver coating did exist and did wear off quickly. About 15 years ago a huge hoard of John II and Manuel entered the coin market, the price of Trachea collapsed for a time, the coins that came in were still mostly silvered , some more than others but with handling the silver coating wore off. The metal mix still contained silver but the coating was a thin layer for visual effect. My coin does not seem that delicate, in fact I bought it before the hoard came into the market. I was concerned at the time of the new hoard that my coin would never regain its buy price again.
