One of the reasons I initially chose my Corelle dinnerware was for the product's durability. The stoneware mugs are not as hardy as the plates and bowls but with the ability to purchase open stock pieces it is not a problem. While unloading the dishwasher, my husband dropped one of the mugs rendering it unusable. I have replaced it with two new cobalt mugs. They are perfect for hot coffee and tea - no dark stains will mar their beauty.