Or quartzite, mica, orthoclase, bauxite, and chert (note that granite is NOT one of the magma-safe igneous rocks).
Also, the iron produced from limonite is identical to that produced from any other iron ore. Iron as a metal should be magma-safe, but the ore itself may not be.
Your problem, Kaspa, may be that you used non-magma-safe mechanisms in the floodgates to link them to a lever. mechanisms in buildings exposed to magma are considered equally with the materials of the primary constituents of the building, thus if you mechanisms are not composed of magma-safe materials, the building will deconstruct and the materials it's made from may deconstruct. I'd suggest either finding magma-safe stones on your map, or producing iron mechanisms to use in your obsidian farm.
According to the Wiki, even limonite is not magma-safe.
I suppose that I'll set up a magnetite-only stocpile around a smelter. And I'll build some mica mechanisms, I have plenty of mica.
But the main issue of my trial was that the lava and the water met in the middle and generated only a "wall" of obsidian that I am now unable to dig unless if I want flow with lava the smelting area.
I'll go with the wiki sample.
At least this time I've been able to equip every one (10) with iron helms, iron shields, iron weapons (battle axes, short swords, spears, war hammers) and iron legwears. I have yet to forge the mail shirt and the gauntlets, and I'll have the militia fully equipped.
Then I'll go for a markdwarves squad, I suppose.
@Lich: I'm curious to know if you'll mange to rebuild the Mountainhomes.
I'm wondering, after the first two hardcoded migrant waves, would there be other waves?