When wax is spilled on natural stone it creates a two-part stain consisting of the wax substance along with an oily residue that likely has soaked into the porous surface of the stone. The remedy also is a two-part: Start by removing the hardened wax, then attack the stain with cleaners that are safe for stone.
Remove any hardened wax using a plastic scraper and working from the outside edges of the stain toward the center, to prevent spreading the stain. Do not use a metal scraper or abrasive material, which can scratch the stone.
Heat up a clothes iron. Lay a white paper towel or white blotting paper over the wax and apply the hot iron over the towel, causing the melted wax to wick up into the paper. You may get wax on the iron, so it's best to use an old one. Note: If the stone has a sealer or other type of finish, test this method in a small, inconspicuous area to make sure the heat does not affect the surface. You can also skip this step if you have any concerns about damaging the stone or finish.
Wet a clean cloth with distilled water, and squeeze out the excess water. Add a few drops of ammonia to the damp cloth and wipe the surface of the stone to remove oily residue left by the wax. Rinse the area with distilled water and let dry.
Apply a poultice if the stain remains: Mix baking soda and distilled water to form a thick paste, about the consistency of peanut butter. Wet the stained area with distilled water, then spread the paste on the stone to a thickness of 1/4 to 1/2 inch. Cover the area with plastic and tape the edges to create an air seal over the poultice; this prevents it from drying quickly, which diminishes its effectiveness. Let the poultice sit for at least 24 hours. Remove the plastic and let the poultice dry completely.
Clean up the dried paste, using the plastic scraper, if necessary. Dampen a clean cloth with distilled water and blot the area to remove all traces of the baking soda. Let the surface dry. If the stain remains, repeat the poultice treatment as needed.