The Marble node is a Procedural texture that can create marble-like noise. It is similar to a Turbulence texture, but more fine-tuned to create marble-like patterns (figure 1).
Figure 1: The Marble texture creates a Procedural noise pattern
Power - Controls the Texture's overall brightness.
Offset - Sets the Texture position in 3D space.
Octaves - Controls the line thickness of the marble shapes.
Omega - Controls detail in the underlying fractal pattern.
Variance - Randomizes the Marble pattern.
UVW Transform - Positions, scales, and rotates the surface Texture.
Projection - Sets the Texture's projection onto the surface.