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.
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.
For most granite and marble tile i install i use either 1 32 or 1 16 inch grout lines.
Proper setting materials for tile 544.
Laying a marble floor without grout is possible so long as proper care is taken to assure your layout is perfectly square.
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.
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.
How to lay a marble floor without grout.
This is what can happen.
Although tile installations can be installed in groutless format the traditional method calls for grout to be placed in the joints between the tiles.
You will be butting the tiles up.
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.
Grout locks or secures the tile besides assurance of straight lines.
Using the correct type of grout.
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.
Do not use tile spacers.
This is true of man.
Literally zero variation in size and all perfectly rectangular.
Before installing your marble tiles without grout consider the function of grout and whether it is appropriate to eliminate the step.
It also keeps the edges of tiles from rubbing against one another as the structure beneath naturally shifts.
This can kick up a lot of grout dust so make sure the area is well ventilated.
It is important to find ingredients that will clean effectively yet be mild enough to cause no damage to either surface.
How to grout marble tile.
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.
Grout works to prevent moisture and detritus from entering and getting stuck in the grout joints.
That s assuming the tiles are indeed perfect in size.