Hallmarked silver - 1937 Coronation coin - paperweight

Hi - I have this paperweight that has what looks like a coin inside that is hallmarked. Is this a common thing to do. I have looked but been unable to find much information about it - perhaps someone here may be able to tell me a little more about it.

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I’ve never heard of this myself. I’ve also not seen those coronation coins in hallmarked silver, they were usually just nickel, or similar. The value of the coin is around £15. The coin and the paperweight, I’m not sure. It looks unusual, but looks almost homemade. Perhaps someone working in a glass manafacturers made it for themselves on the coronation as a keepsake? It’s very interesting, I’m sorry I can’t tell you more.