If they are floor tiles rather wall tiles they might be ok. I was also warned off slate - apparently it's too soft and scratches easily.

It can be more complicated than just laying a few tiles depending on the type of stove. If the stove has legs and is certified not capable of raising the hearth temperature above 100C then you can lay a thin slab of glass, granite or tiles over almost any floor surface (eg over a wood floor).

Examples of this type:




The slab only needs to be 12mm thick but it must form an 12mm step to discourage people putting rugs too close.  I went for a 20mm thich slab of granite which I got from a local stone mason. I took them a plywood template. It was originally an offcut of a kitchen work top and had a gloss finish but they honed that off for me to make it matt. The area of the slab must be bigger than the foot print of the stove by a certain amount: 





If the stove/fire is not certified as above then you need a much thicker concrete slab called a "constructional hearth" to stop fire spread.

Example of this type


The thickness has to be something like 125-150mm. This either has to be resting on the ground/foundations or projecting from the wall with a 50mm air gap underneath - either way it's major structural work. If you need to go this way I can look up the exact details. Some people have screed floors only 60mm thick with insulation underneath and that isn't sufficient for this type of stove.



If you haven't yet purchased a stove I recommend the Clearview range.