Marble thresholds are a great way to transition between the flooring in two rooms. Since the threshold is approximately 3/4 inch thick, it can make up the difference in height between two floors, or just make an elegant transition between two materials. Marble thresholds are sold in standard lengths and widths. If you have a doorway that is not a standard width, you'll need to cut the threshold to fit. Marble thresholds can be cut the same way that marble tiles are, with a tile wet saw.
Things You'll Need
Tile wet saw
Line up the threshold with the doorway where it will be installed to check the fit. Mark the space to be cut with a pencil and straight edge. Check this fit twice; it should be snug against both ends of the door jamb when installed.
Turn on the tile wet saw, and check to make sure there is plenty of water in the reservoir beneath the blade. Line up the threshold with the blade where you'll make the cut.
Push the marble into the blade carefully. Do not exert force; let the blade chew into the marble, pulling it along as it does so. Allow the marble to dry before installing.