It is rarely a good idea to put hot pans directly on a countertop. Even though a manufacturer may claim a countertop is totally heatproof, this is often untrue. Extreme heat may cause everything from minor, easily repaired surface burns to virtually irreparable cracks or melting. Here is a quick guide to dealing with heat damage for various countertop materials. DIY Resource: http://www.networx.com/article/repairing-heat-damaged-countertops
Plastic Laminates: To remove a minor, light-colored burn from laminate countertops, coat the spot with a baking soda paste for about 30 minutes and wipe it off. Laminate surfaces with deeper burns typically need to be replaced, but it may be possible to replace the surface of just one section.
Wood: Sand away burn marks on butcherblocks or other wood countertops with 120-grit sandpaper, then go over the area again with finer 180-grit sandpaper. Add a wood filler if needed. Then rub in a solution of four parts mineral oil and one part melted paraffin wax to protect the wood. For varnished or painted wood surfaces, it will need to be stripped with a food-safe chemical stripper. After sanding away the burn, replace the varnish or paint.
Solid Surface: Heat can fairly easily damage Corian and other solid-surface countertops. However, the damage can also be reversed fairly easily by sanding around the burned spot. Then cover the tracks of your sanding with Bon Ami or other abrasive cleaner. Serious burns may require an electric sander. In either case, wet the surface to minimize dust. Severe heat can crack the countertop, which will probably require professional repair. DIY Resource: http://www.hometalk.com
Stone: Many natural or engineered stone countertops are virtually heatproof. However, some stone surfaces are liable to crack if exposed to extreme temperatures. Again, these are best repaired by a professional, but some stone epoxies are available for repairing small cracks.
Concrete: Extreme heat can also crack or burn concrete countertops, though penetrating sealers can help prevent such damage. Use a tinted two-part stone-grade epoxy to repair hairline cracks in concrete. Consult a professional for larger damage.
Tile: Most ceramic and natural stone tiles are virtually heatproof. However, if an individual tile gets cracked or burned, it can be replaced fairly easily. Here's basic instructions for tile repair: Use a grout saw to remove the grout all the way around the tile. Tap the tile with a chisel until it breaks apart. Then use the chisel to remove all the tile pieces, as well as any remaining grout or adhesive. Put adhesive on the back of the replacement tile and press firmly and evenly into place. Grout around the tile and wipe away excess grout before it dries, then seal the new grout.
Meta & Glass: Glass and stainless steel or other countertop metals are virtually heatproof.