Mystery 18kt Estate Cufflinks

[DeathandTaxes]

My father passed away and in the bottom of a small bag of random odds and ends I found these cufflinks.

I have no idea about them, other than they show a mark for 18k on the back and the jeweler I took them to said they were genuine 18kt gold (he said they are two-toned - green and regular 18kt gold).

There is no maker's mark or anything else I can see on them.

I have done my internet searching and can find nothing like them.

Any clue as to what they are? Who made them? Time period?

Thanks in advance for any information that you can provide.

 

[Sky56]

My guess, though unspecific - quite old (pre-1920), European