Food warming mats are generally safe for heat-resistant countertops like stainless steel, tile, or sealed wood, but caution is crucial for natural stone (granite, quartz, marble) as prolonged heat can cause damage, cracking, or discoloration, so using a trivet or heat-resistant pad underneath is best for natural stone, quartz, solid surface or delicate surfaces to avoid costly damage. 

Not only can the mat cause cracks, it is more than likely to cause failure with your seams. With solid surface countertops you need to remember that not all seams are visible.

Look for mats with safety features like auto-shutoff, and always start on the lowest setting, especially on stone surfaces, to prevent heat buildup.

Using any of these products may cause damage that is not covered by any warranties.