curious

Hi, can someone please help me identify this? I know very little about silver so not sure if it’s silver or not but it’s soft and very bendable. I’ve been using it as a bookmark but I don’t think it is one. I bought it at the Goodwill store , they had 10 or so, all different designs, but no one knew what they were. They all have the same small loop in the same place so I think they must be used for something. There is a mark of a bull’s head and the letter c in a circle just above the loop. All had the same mark. Thank you.
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