1732 Spanish Pillar Pendant

Hello and welcome to the Forum
The "coin" you have pictured is a casting of an actual salvaged coin. These were made as keychains and sold as tourist trinkets in the late 60's or early 70's. Many were made by famous salvage diver Robert "Frogfoot" Weller and he told me when I dove with him in 2001 that he chose that coin to cast because it was so recognizable in both the salvage community and the numismatic community that no one would mistake it for a real coin. Then came ebay, and those were all over early ebay as "rare pillar dollar coin". Great piece of history but not even made of silver (I am not aware of any being cast in silver). Below is a picture of the actual coin from the book "The Treasure Galleons" by Dave Horner.
If I can find it, I will post of photo of my 1732 (same casting but without the keychain loop) that I got from Robert Weller's son when he was selling some on ebay as "copies" many years back.

Thanks for the info! I do believe that this is indeed silver, though, as I threw it into a batch of silver jewelry to clean using the aluminum, salt and baking soda mix. Tarnish melted away instantly and had the unmistakable smell that true silver gives off in this chemical reaction. Which sent me down this rabbit hole! Unless there's another metal that does this?