The products that we recommend for architectural interior are sawn edges tiles. These products are available with natural or machined surface
With regard to size, we can suggest different pattern, from square pieces, to rectangular joining together, to alternate rows.
For the flooring, we highly suggest the machined surface tiles, mostly in the new flamed and brushed surface. This surface is unique, because it combines the flatness of the flaming with the softness of the brushing. As a consequence of the fabrication process the thickness is uniform, so that they are easier to install.
Other surface finishing available are: honed, polished or semi-polished.
On the other hand, for interior vertical walls, a very nice suggestion can be natural cleft (indeed showing some irregularity) that would create interesting light effect.
Considering the compressive strength of porphyry stone (30.000 psi), the fact that flooring areas are pedestrian, the thickness selected can be 1” or even less. We suggest to install these products on mortar bed and then grout.