A little more information if you'd like. The rank represented there is a Chief Master Sergeant, the top enlisted rank in the AF (E9). Most wings in the AF have a specially designated position for a Command Chief. Think of them as the main enlisted advocate and advisor to the wing commander, normally a Colonel or Brigadier General. Most Command Chiefs have their own unique challenge coin that they can present to other AF personnel when they've done something worthy of that recognition. Since Keesler AFB in Biloxi is primarily a training base (I had my technical training there in 78-79) lots of people transition through there. Someone obviously lost it while frolicking on the beach.
It varies. I was in the AF for 30 years and was a Chief, but not a Command Chief. Sometimes people were given coins for briefing a visiting dignitary or VIP. Other times they might've come up with a new, innovative way to do something that saved time and/or money. Some were given for heroism in conflict. There's really no set guidance and it's all the prerogative of the person giving the coin. Without knowing who the coin you found belonged to its hard to say.
