Marble tile spacing

I have about 500 12x12x3/8 tile to place on cement in our new
house. I want to place the tile touching each other without spacers. Can I realistically do this and grout the top joint where I
can or do I need a minimum spacer between each tile?
Thanks for your thoughts.
Alex

 

ther a re afew reasons for grout joints one being tile are different sizesand the joint helps keep everything straight and in line also the tile sitting next to each other and butting the next will cause the tile to rub or bump together as the floor flexes when being walked over causing the tile to chip at the edges,also the joint helps with the imperfections of the tile heighth wise and the little bumps and rises and dips in the floor,so to answer you're question yes you would need a joint in the tile,the only time i use a real small joint ,1/16 is when setting marble or limestone and then use unsanded grout