It might be under the computer equipment, if it's small enough to slide under a harddrive, printer, etc. Unless one of the movers took it which is possible...
I placed a pearl pendant on top of the harddrive and I lost it. I found it almost a decade later. It was in the same room but in a container. I can't remember ever putting it in the container.
My husband lost his wedding band and that too, went MIA for 7 years. I finally found it among some boxes... we have too much in our lives, no wonder we can't find anything plus we're both hopelessly absent-minded.
Now wait for the piece de resistance.... I lost the diamond from my engagement ring one day on the way to work. I had actually took a spill on the pavement and didn't even realize until I felt my ring. I ran back to the same spot and found the diamond embedded in the tar, point side down. It had been a very hot day (I was sort of lightheaded that day). This was right along 42nd Street in NYC!!! If it's yours, it's meant to come back to you.
So keep your hope up, it is possible your DF laid it somewhere else instead, like in his pocket or dresser or even medicine cabinet?