This has to be one of the most frustrating things ever. I was photographing a "budget" Trajan Decius silver Antoninianus outside for a client (I find outside light is best).
Then, with no warning, a gust of wind lieterally picked my coin up and blew it away.
I never could find it, so I figure, at best, it will be in the ground another 2000 years before someone finds it. Here's the pic. Lemme know if you find it!