Board Thread:Ask the Staff/@comment-32344126-20170620172704/@comment-4075764-20170623062346

I believe the closest thing to a "Magma-Lapis" would be Pyrite- a type of rock commonly found in coal, sedimentary rocks, and is associated with fires. It's also common element found in Lapis Lazulis, along with Sodalites and Calcites.

It's also known as Fool's Gold, so there's that.