That is a great looking base, was it a 3D print/resincast base or did you use some kind of special paint to make the black lava flow?
Citadel Mordant Earth. It's a really weird thick paint, but you cake it onto a base and it dries over 2 days naturally cracking. The base was White Scar > Yriel Yellow > Fire Dragon Bright > Troll slayer orange > Wild rider red > Evil sunz Scarlet > Mephiston red (a little bit less of each colour each time) to create the lava effect, and the mordant earth cracks like dried lava!