John
They look like a quarry tile. However, the glaze looks a little shot on them. I would therefore do the following:
1. Deep clean (To get all the crud out of the faces and the grout lines)
2. Allow to thoroughly dry. (Use a snail drier that will speed things up)
3. Seal them with an impregnating sealer(This will stop a topical wax or polish sinking into them)
4. Either wax them, or polish with Tile Brite or apply a topical sealer.
Kevin