Can I use my iPhone 5 on any service?

I bought a iPhone 5 last summer at best buy on my Verizon service. Well due to financial reasons I decided to terminate my contract and switch to Virgin Mobile. I got an android because it was cheap but I defiantly miss my iPhone. Today I was playing around with my old iPhone found a sim tray. Opened it and behold a verizon SIM card. I didn't know they had SIM cards! Anyway since my 4g virgin mobile phone came with a SIM card… If I swapped them do you think I could get service on my iPhone. It seems like it's unlocked.

If it's unlocked, you can do it with no problem

Hi, iPhones 5 from Verizon shall be unlocked out of the box. So it should work.
If there's any problem, please take steps described in this procedure:

http://www.flyunlock.com/iphone-unlock-procedure-instructions

I might need to restore your iphone with the new SIM.