What Is Marble?
It's good to know what marble is in order to understand how it behaves. It's a metamorphic stone, which is formed when sediment crystallizes under great heat or pressure to form hard rock. Marble is not the hardest of the these stones, however, making it porous and therefore susceptible to staining. Granite is also metamorphic and much harder (no staining), while soapstone is less hard (more staining). Marble is also formed out of calcium carbonate, giving it a chemical structure that reacts easily with acids and leads to etching on the surface.
Due to all this, marble requires some maintenance to keep it pristine, though many prefer the gradually aged surface with etches and stains that blend into the grey veins over time. Think of marble as the jeans of countertops — they will work better and better while wearing and aging gracefully, giving them a unique and organic character.
What Types of Finishes Does Marble Come In?
There are two main types of finish you can get, but I would recommend a "honed" finish as it is the easiest wearing. Before I knew the difference I had a polished finish installed in my kitchen, and it's great, but it definitely feels messy more easily and makes me want to clean it more often. The shiny finish is the more uptight of the two.
Honed Finish - Created by sanding the surface so that it has a soft, matte finish, honed marble won't show scratches as much, shows the stone off as a little less bright and is more susceptible to staining as the pores are open. Sealing is therefore the solution.
Polished Finish - Polished to a shiny exterior, this finish won't stain as easily but it can scratch and etch. Polished surfaces are shiny and bright, but they will be worn down in time. If you prefer the worn look, go right for honed and skip the polished.
Can I Clean Marble Easily?
Yes you can! Whether you are simply cleaning down the whole countertop or working out a stain, marble cleaning is easy. Warm water and dish soap sprayed onto the counter works perfectly and, for stains, mixing baking soda and water into a paste and leaving overnight lifts stains out. I've had my marble countertops for about two years and I'm not a neatnik, AND I cook every day; they have no stains and a little etching that can only be seen in certain lights.
Does Marble Need To Be Sealed?
Yes. Because unpolished or honed marble has open pores, it is important to seal it if you want to limit stains over time. This can be done professionally at the beginning and then as a DIY in an ongoing fashion. While many people have commented that they have never felt the need to do this, it's not hard. Over at the Petch house they have done a bunch of demos and there's a also a simple step by step at WikiHow on how to apply Penetrating Sealant.
Why Is Marble Affordable?
To be clear, not all marble is affordable, but Carrara marble, despite coming from Italy is one of the cheapest stones due to its greyer coloring (luxury marbles, like Calacatta, are brighter white with darker veins) and its porous nature. Some people don't like the grey cast, and because it does require maintenance, it is never specified for rental homes, making it a slow seller and therefore lower in price. Americans generally don't like maintenance.