Mecury is geologically inactive.

by roland , Tuesday, July 09, 2013, 07:16 (4154 days ago) @ JDQuackers

technically, it does have lava, even if strictly underground.

I believe that's called magma, as in liquid hot magma (read in Dr. Evil's voice). It's not lava until it's no longer > underground

Now that's some good science :)

As far as Mercury having lava in Destiny, the Traveler infused Mercury with his space magic so anything goes. In our actual solar system though, no, there's no lava fields on the surface of Mercury.

... but if it did and we could go there to fight some Vex scum, we'd want there to be lava fields because it's just way more fun that way.