They are travertine tiles and the cracking is a direct result of having the tiles butted against each other with no grout lines.
Marble floor tile no grout.
Using the correct type of grout.
This is what can happen.
As you work be very careful to avoid the edges of the tiles themselves as you do not want to chip or scratch them.
Before installing your marble tiles without grout consider the function of grout and whether it is appropriate to eliminate the step.
Even if rectified tiles allow you to avoid using grout without having the result look unaligned the materials are still in danger of being chipped or damaged.
Both marble and grout are easy surfaces to clean when you apply the proper cleaning routine.
It also keeps the edges of tiles from rubbing against one another as the structure beneath naturally shifts.
Do not use tile spacers.
This is true of man.
Grout locks or secures the tile besides assurance of straight lines.
For most granite and marble tile i install i use either 1 32 or 1 16 inch grout lines.
Grout works to prevent moisture and detritus from entering and getting stuck in the grout joints.
Set the next piece of tile adjacent to the first piece being sure to repeat steps 2 and 3 for every marble or travertine tile you install.
You will be butting the tiles up.
Using a grout saw or an electric tool such as a dremel with an appropriate attachment begin to remove the grout from between the marble tiles.
For the size of the tiles you are using the minimum grout line width for the 12 wall tile is generally 1 16 and for the 24 floor tile 1 8.
Laying a marble floor without grout is possible so long as proper care is taken to assure your layout is perfectly square.
How to grout marble tile.
Proper setting materials for tile 544.
Perfectly cut edges will not perform better than regular tile when friction occurs so they can still cause a variety of problems if you opt for a no grout tile installation.
I ve seen non grouted ceramic granite marble limestone in a wide variety of locations airports subways palace and museums all without grout lines spaces cannot recall in my 81 years noticeable ugly signs of an issue caused by lack of grout space.
Literally zero variation in size and all perfectly rectangular.
Instead line up the corners of the tiles and use your rubber mallet to gently tap the surface of the marble or travertine until it is butted up tightly against the adjacent piece.
Although tile installations can be installed in groutless format the traditional method calls for grout to be placed in the joints between the tiles.
That s assuming the tiles are indeed perfect in size.