Silestone is a brand of engineered quartz countertop material used as an alternative to granite and other hard materials. Quarts countertops are durable and long-lasting, but they can chip if something is dropped onto the counter. If a chip occurs, you can either glue it back into place or fill the chipped area with fast-drying glue and then buff it to blend in with the rest of the countertop. Since most Silestone countertops have variations in the colors, the patch will be nearly invisible, if done properly.
Clean the chipped area with an ammonia-based cleaner and a soft cloth. Allow the area to dry.
Fill in the chipped area with a layer of fast-drying glue. Allow the glue to dry overnight. Fill in the area again with another layer of glue. Continue to add layers until the chip is completely filled -- slightly above the countertop's surface level. Allow the glue to dry thoroughly.
Cut off the top layer of the glue by holding a sharp razor blade at a 45-degree angle to the surface.
Sand the area with fine-grit sandpaper to remove any bumps.
Buff the area with a soft cloth and a quartz polishing cream, to restore the original brilliance of the countertop.