I've a matching set of Grisogono 'lightning'-shaped wg + blak/wht diamond earrings and ring. I wore them to my cousin's wedding, morning ceremony, then luncheon, then dancing +++++ till later and later. The earrings (post and clip) became more painful as the day turned to night. By the time the 'happy couple' hit the floor for the first dance, the earrings were killing me. I had to take them off.
10 years later I was still looking for the earrings. I'm sure somewhere on tPF I wrote I was resigned to the fact I'd lost them.
Last year, I found them again.
I even lost a Cartier lion ring my mother gave me. I wore it once, and then - no idea. There were times I thought perhaps I imagined that she gave it to me and lost my mind and not the ring.
I found that too, even more recently.
Moral of the tale, never give up looking, never give-up hope. You probably do what I do, put it somewhere so safe you end-up hiding it from yourself.
It doesn't matter how expensive or inexpensive things are, I absolutely hate losing/mislaying them.