How does it works? / How does i customize the shader?

There's basically four parts that control the shader: The Marble Base, and the three Stone Variants.

1. The Marble base has 2 main options, the flakes and grain sizes and the base colour for the marble.
2. Each Stone Variant has several options that lets you customize the material. Ranging from a random seed and the roughness of the edges of the shapes to the rock patterns and cracks.
3. The other two parts basically work the same as described in the previous point but let you customize the other two Stone Variants.