1. Take a utility knife and try to scratch it in the corner of the room. If the knife scratches it, it's stone. If it doesn't and just leaves a metal mark, or no mark, it's porcelain
2. Take some cleaner. Any alkaline or tile cleaner and clean a section. Use a rag or soft brush.
You'd be surprised how many people don't know what kind of floor they have.
Why not just pull a floor register, look to see if its stone, apply alkaline and clean with a spinner and be a hero
You think that was a tough ID, you should see the latest Corian Marble look alike counter tops