For this diorama, use for the high-density, 20mm-thick telgopor base, to which I covered with a hard plastic, applying it with a brush, to give it a limestone rock texture.
For walls, use polyphane. As for the texture, use a ruler to give it this look and break pattern.
Use as black base, then lighten and make the effect of worn using largely light pink, and on this, in some parts, lavender.
I made it compatible with a throne made previously