Metal conducts heat, but some metals conduct better than others.
Copper:
Copper is conductive, transferring heat effectively from the stove to the food. Unfortunately copper tends to get into our food, and is unhealthy unless taken in very small doses; we do need a very small amount of copper, but we tend to get too much.
Stainless Steel:
This is not nearly as conductive as copper, but it is fairly neutral in terms of how it affects our food. There is some concern about the constituent metals getting into the cooking and our diets, but the problems appear to be slight. Stainless steel is slow to heat up, but it tends to heat very evenly over the cooking surface. There is no hot spot in the middle with a colder rim.
Stainless steel tends to stay clean, so it won’t contaminate the food with corrosion.
Aluminium:
This conducts well, and heats quickly, but it can have a slight issue with the centre heating up before the edges. The downside to aluminium is that it reacts badly to acidic foods like tomatoes, which may prove bad for us.
Iron:
This tends to heat slowly but evenly. Some iron in the diet tends to be a good thing, but the surface will rust unless looked after.
Stonewell & Flavorstone Cookware, Pan
Combining different mediums for cooking is complicated, as different metals expands at different rates. A pan made of two dissimilar metals will tend to warp as the metals expand at different rates. Considerable engineering skill is needed to combine different materials into effective cooking pots.
Stonewell pans have an aluminium base for high conductivity. But the cooking surface is a stone coating that will not negatively affect food, and designed to be non-stick. Extremely long lasting, these pans combine the best of all cooking mediums.