Slate floor is a traditional style of flooring that is made with natural stone. It is considered to be fairly eco-friendly because it is quarried as opposed to being manufactured. It is also a form of flooring that has been used for hundreds of years and is very durable. However, slate flooring is a porous material and so it can stain if it is not being sealed. For this reason, you should always make sure that this type of flooring is sealed when it is first laid and then re-sealed when needed.