I get these questions the most… What is the difference between Marble and Granite? Marble is sedimentary stone formed by pressure and time. Granite is igneous rock made out of lava in the heat of a volcano. What is the difference between dimensional stone and slab? Dimensional stone is three dimensional blocks that can be carved. Slab is 3/4 or 1 1/4 inch thick and usually used for counters, floors and coverings. Why is granite so hard? Granite is composed of mostly silica which is also what quarts crystals and glass are made out of. This makes it extremely durable but very hard to work with. Why marble then? Marble has a classic beauty that granite lacks. The fact that it is softer and easier to work with makes it perfect for low use areas such as vanities and fireplaces.