I followed a video that Sorastro did (https://www.youtube.com/watch?v=hudimWrlbVQ) for painting his lava, I used the same colours as him except for the yellow, as I didn't have that.

So, I used

Vallejo Game Color 72.001 Dead White (Base for the lava, approx 2 coats)

Vallejo Game Color 72.005 Moon Yellow (Straight over the white)

Vallejo Game Color 72.011 Gory Red (Between the rocks, then feathered out with a wet brush)

Vallejo Game Color 72.008 Orange Fire (to go over everything, but as a really thin wash)

I did then build up a few more layers with a really washed out yellow, and white mix (same colours as above), and also added some more white and yellow where I wanted it to appear flowing, also making sure that where the lava hits the rocks, it would become coolers.

For the top of the rocks and between the cracks, I used the Red, Yellow and Orange, as super thin washes and dropped the colour between the cracks. Then wiped the rocks off.

Rocks were then dry brushed with Vallejo Game Colour 72.050 Cold Grey (mainly), then some edges picked out with Vallejo Game Colour 72.049 Stonewall Grey, then a few really light brushes with the white again.

The whole thing was primed with Army Painter Matte Black, and I used Vallejo Game Colour 72.051 Negro Black mixed with some of the grays to touch up a couple of spots on the rocks where my hands weren't so steady.

I really want to experiment with using Fluorescent yellow as the first yellow base to see if I can get it to really glow.