Sulfur causes silver to tarnish.
Silver tarnishes due to sulfur.
Sulfur is an element and as such no silver would be found in pure sulfur except as a trace element.
The combination of silver and sulfur is silver sulfide (Ag2S). This is a compound with a metal (silver) and a non-metal (sulfur), so we use the metal's name with the non-metal's name changed to end in -ide.
sulfur
Ag2S = silver sulfide
Ag2S
Sulfur is an element and as such no silver would be found in pure sulfur except as a trace element.
The combination of silver and sulfur is silver sulfide (Ag2S). This is a compound with a metal (silver) and a non-metal (sulfur), so we use the metal's name with the non-metal's name changed to end in -ide.
The silver sulfide is Ag2S.
sulfur
Ag2S = silver sulfide
Ag2S
All coins come from a mint. Casino coins are sometimes solid silver.
When silver is combined with sulfur, it forms a layer of black silver sulfide. Being exposed to air and sulfur will cause any type of silver to tarnish.
There were proof sets made in 1974 and 1975 where all 8 of the coins were silver, and proof sets made during those years when none of them were silver. Assuming that your coins are in a set, check the 1 Cent coin - if it looks silver, then all the coins in the set are silver; if it looks bronze, then none of the coins in the set are silver.
Just recently with the advent of bullion coins such as the American Silver Eagle. Coins intended for circulation were never 100% silver because silver is simply too soft of a metal for coinage. They were 90% silver in American coins until 1964 for dimes, quarters and half dollars, but other than bullion coins, no coins are made of 100% silver.
Silver is a metal. Sulphur is a nonmetal.
No British circulating coin has contained any silver since 1946. From 1919/1920 to 1946, all British silver coins contained 50% silver. Prior to 1919/1920, all British silver coins were made from sterling silver or, 92.5% silver.