Identifying a Chinese knife coin.

I recently came into a coin and banknote collection from a deceased collector friend. He was a Chinese native with a decent collection of artwork and furniture that we were selling off bit by bit to help fund his treatment later in life, which is the only reason I believe these coins may hold some actual value, as his collections and pieces in other mediums were all very valuable and real in either artistic or historic value.

I've also had the bank notes valued and they are also of a decent value. This brings me to these coins, circle coins with holes, spade coins and I'd like to start with the knife coin in the collection. I don't know how to identify the markings, the shape, or the metal it's made from. I imagine these are commonly forged and reproduced.

I would appreciate any assistance. I don't have an accurate scale but it weighs about the same as a medium egg :)

Images below and I included an edge image as I'm sure the experts among you will be able to tell metal or the nature of how it was shaped by the filing pattern or some such other sherlock holmes magic.

Hello

not expert but seem to have a strange shape for me (Of all the ones I've seen so far)
Some more information here
But wait for another opinion
https://en.wikipedia.org/wiki/Knife_money

modern replica of this, only a few known all in museum.

Quote: "jane6301"​modern replica of this, only a few known all in museum.
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​Thank you very much!