The seeds of the coffee fruit after harvesting and separating from the fruity pulp is called the raw coffee beans. This then needs to be roasted and subsequently ground or even powdered, to make coffee.
For small batch home roasting, the type of pan does not matter. In this video, a French copper pan is used. Cast iron skillets are excellent for heat transfer, however, the oils from the beans can make the skillet eventually smell of coffee. Stainless steel does not have this issue. Copper bottomed or clad stainless steel pans are ideal as it gives ease of maintenance with excellent heat transfer.