This story covers installing stone tile.
Stone tile requires the same firm and level setting bed as ceramic tile -- only more so. Because stone is brittle and the minerals that make up its pattern are not perfectly "cemented" to each other, it is subject to fracture along the grain lines.
Stone also suffers from the normal physical inconsistencies found in any natural material. Some pieces might not be exactly as wide or thick as the others. Adjust length and width by cutting the tile with a wet saw and accommodate differences in thickness by adjusting the amount of mortar you spread.
When set, the top edges of all tiles should be flush. Back-butter each tile before you set it in the mortar bed and test it to make sure its edges are flush with its neighbors.
Most stone tile comes from the factory with beveled edges, so cutting a tile will leave it with an unbeveled edge. Hone the edge of the cut tile with a rubbing stone or with sandpaper wrapped around a block of wood. To polish a tile to a high sheen, use progressively finer grits of carbide sandpaper (from 120 to 600).
About 10 hours for an 8x10-foot room. Allow 3 to 4 hours for grouting and cleanup on the next day.
Chalk line, tape measure, carpenter's pencil, power drill with mixing paddle, notched trowel, beater block, rubber mallet, grout float, 4-foot metal straightedge, wet saw, dry-cutting saw
Marking, setting, and cutting tile
Remove existing flooring, repair or replace underlayment
Thinset mortar, stone tile
Lay out a dry run so the edge tiles are the same size. Then snap lines as guides. Using white thinset mortar for light-color tiles, trowel thinset on the subfloor and back-butter the tile. Set and level the tiles, adding mortar to the back as needed. Line up the tiles with a straightedge.
Let the mortar for the edge tiles cure for 24 hours. Then mix a batch of unsanded grout, just enough to cover a small section. To keep the stone tiles from absorbing too much water from the grout, wet them with a spray bottle. Apply the grout with a float. Remove excess grout from the surface of the stone. When the grout has set for about 15 minutes, wipe the haze with a damp sponge. Finish grouting the entire installation, working in sections so you can clean the excess before it hardens. When the grout has completely cured, seal the tiles as necessary.