I don't know about the difficulty of cutting the tile to 2x2, but it should be ok, we used quartzite 1x3 for our shower floor, same as for the shower trim. The walls are 16" quartzite. We sealed it ourselves, our tile installer told us to 'flood the floor' with sealer wait 15 minutes and wipe off excess, then repeat until water beads on the floor. It took 4 applications to get to that point.

Slate cuts like butter with s wet saw. No worries there.

As to using it on the shower floor, it depends on the quality of the slate. If you have a nice tight-grained honed slate, it could perform just fine.

If you have a inexpensive natural cleft slate that has a very loose grain and sheds fragments, nope, obviously it's a bad idea on a shower floor.

As to your waste...can you rethink your dimensions at all?

If you keep the 6x12s and the 2x2s, you'll end up with about 17% waste from each tile. Keep the 6x12s but change your 2x2s to 3.5x3.5s (less cutting) OR 1.75x1.75s (a lot more cutting) and you'll have zero waste.

If you're really set on 2x2s on the floor, then change your wall tiles to 5.75x11.5s OR 6.75x13.5s and again, you'll have zero waste.

If you use something other than the slate on the floor, then consider using the small leftovers in a deco band like lynneblack shows in her shower photo. I prefer deco bands to be made up of odd numbers of rows. Or you can set squares on a diagonal in the band.

Just a couple of ideas to mull over. But with a little thought and creativity, it's very easy to get close to zero waste when cutting tile.

lynneblack:

Thanks for the photo and the tips regarding sealer. How long has it been since you sealed the quartzite and how is it holding up?

mongoct:

I believe the quality of the slate is decent. I had posted about this same slate a while back (can't seem to find my posting for some reason). You and Bill Vincent suggested some tests I perform with the slate (eg soaking it, tapping with a trowel, looking at its edges). Based on performing those tests, I think it should hold up. If I could find an inexpensive 2x2 gray/blue slate lookalike for the floor, I would consider it just for the extra peace of mind.

I like your ideas for minimizing waste. I am flexible with the size of the slate so that is something I'll think about. I need to start a new post for discussing tile size and layout since I'm planning to mix 12x24 porcelain with this rectangular slate.

It's only been sealed for about a week, so I can't really give you any idea of long term durability. On the recommendation of the installer we used Stonetech Bulletproof. He stressed that porosity of quartzite varies even within a single tile, which is why he prefers to 'flood' the area so that the more porous areas absorb enough sealer, then remove excess after 15 minutes or so. He recommended re-sealing it every 6 months to a year, mainly because the water here is highly alkaline and he said that will destroy the sealer.