Granite is volcanic (or Igneous) rock. When molten material from the Earth's core called "magma" comes up to just beneath the Earth's surface and cools, it becomes Granite. Granite is very hard and extremely durable. It has a very grainy structure and can be polished well. This type of stone comes in a variety of colors ranging from salt and pepper to reddish brown to jet-black. Granite: Primarily made of Quartz (35%), Feldspar (45%) and Potassium. Usually in dark colors. Contains very little calcite, if any. Provide a heavy crystalline and granular appearance with mineral grains. It is very hard material and easier to maintain than marble. Yet, it is still porous, will stain, and much harder to remove scratches if they occur. There are different types of granite depending on the percentage mix of quartz, mica and feldspar. Black granite is known as an Anorthosite. It contains very little quartz and feldspar and has a different composition than true granite. Granite is a wise choice for heavy traffic floor medallions.