Chaps...
Fixing natural stone ranges from "Easy Peasy" to " Bloody Challenging"
Good quality wet cutter and grinder essential. Variable speed grinder and polishing kit advisable. Good quality ( easy to use ) sealers also advisable.
Firstly depends upon your substrate...
Concrete, self levelled, plywood, Ditra Mat etc etc
How level is it ?
This applies to all tiles !
How big are the tiles ?
Many natural stone tiles are supplied in Opus Romano pattern or similar, 4 or 5 sizes of
tile in a repeating pattern. ( can scramble your brain at times )
Many or most types of natural stone are very brittle so you should be using a solid bed trowell and aiming for 80 to 90 % coverage, sometimes back buttering of tiles.
Some types of marble tiles do not have straight edges, and appear to be rough, these can be easier to lay as they are more forgiving. But bear in mind these also take more grout !!
The likes of 600 x 400 travertine and limestone are often required to be laid in brick fashion, so there is little margin for error as tiles all have to be level to avoid lipping.
Slate can be very time consuming as comes in many different thicknesses and requires grading prior to fixing & then fixing, starting with thickest tiles first, working down to thinnest ( increasing your bed size ) slate also requires the most sealing and cleaning. ----- The ridges in the slate tend to hold grout, which is not always apparent until the grout has dried. Some slate tiles come in larger sizes - 600 x 600 for example, these are very difficult to bed in & are just as hard to lift up and re-bed. However the beauty of slate is that it is made up of layers..... So it is possible to chip of some "lipped ridges" with a hammer and chisel after laying to even out.
Sandstone also requires much sealing as it is very absorbent, often comes in large format sizes and different thicknesses. Back buttering required on larger sizes.
The advent of "cheaper grade" travertine is also a problem. This "honed and filled variety" sometimes known as " commercial grade", is inferior to the top grades of travertine. The cheaper grade has more filling and usually more holes in the back of the
tile. Care should be taken when fixing onto floors to fill in any "holes" on the back with your adhesive prior to fixing.
Granite is one of the harder tiles to cut, as is the jerusalem stone type.
Price accordingly to do a good job as very time consuming.
Many or most types of marble floor tiles require ( or customer prefers ) beige or limestone grout - this is best to be sealed after grouting - allow extra time and cost for this !!