de Buyer roasting pan is made of MINERAL B ELEMENT iron which is a 100% natural mineral material.  

The professional way for sealing, browning or grilling food. Once it reaches temperatures above  284ºF (140º C), the steel roasting pan seals the food on the surface, resulting in the caramelization of the natural juices -this processed called the Maillard reaction. A crust forms, preventing moisture from evaporating. The food becomes brown and crusty on the surface, tender and soft in the middle. Ideal for cooking on hot coals