How do I dig below the magma seas?

I dug right to the magma seas in Dwarf Fortress, but now I'm stuck.

Below the layer I'm on now is only semi molten rock which I can't dig through. I know that there are adamantine veins but I can't access them because I'm surrounded by magma or semi molten rock on this level. Is there any way I can dig down anyway?

Solution 1:

If you can't dig across to get to the adamantine, you'll just have to start from above the magma sea and dig straight down once you've located the adamantine veins. And if you haven't already: breach into the magma sea by channeling to make lower levels visible.

To quote the Simpsons: "No, dig up, stupid." :)

Solution 2:

Couldn't you channel through the SMR and then use water to solidify a section of magma into obsidian? This would allow you to dig down another layer, pour more water, etc., until you make it through the magma.