Yes, marble is a completely natural stone. It is formed deep within the earth over millions of years.
It starts as limestone, a soft stone made from the skeletons of tiny sea creatures. Under immense heat and pressure inside the earth, this limestone recrystallizes. This process, called metamorphism, transforms it into the hard, beautiful stone we know as marble.
The unique swirls and veins in marble come from different mineral impurities, like clay or iron oxide, that get mixed in during this formation. Because it is made by nature, no two marble slabs are ever exactly the same. So, marble is a 100% natural product of the Earth's geology.
