Marbles - A Procedural Marble Shader
MARBLES is a fully procedural, photorealistic marble shader designed in Blender. Clean or aged, with simple or elaborated patterns: virtually any type of marble can be easily recreated.
Compatibility with both EEVEE and CYCLES (the latter is highly recommended though to get the most out of the shader).
WARNING: might be heavy on performance, if you are experiencing slowdowns, consider disabling SUBSURFACE SCATTERING (weight to 0).