Okay. I haven't explicitly done any testing, barring making sure that hell riders don't instantly fall over dead every single time, so I'm operating under the assumption that "everything SHOULD work in theory, but this is not theory, this is Dwarf Fortress."
CHANGES BEING ADDED:
Explicitly defined a hell material.... but it's still ice, basically. It has a fixed temp, no melting/boiling/ignite points, is undiggable, and it looks like ice.
Iridium, a high-tier metal that takes a lot of effort to smelt. Comes in the form of Native Iridium, and I tried to make it semi-rare, but not impossible to find. However, in order to smelt it.... 1 boulder of native Iridium, 1 boulder of Oxyline, and 1 bar of fuel, steel-making style, will return... a boulder of Processed Iridium. You still can't use it for metal. You need to smelt 2 boulders of Processed Iridium and a boulder of Magmaline, and it'll give you a single bar of Iridium. Have fun!
Oxyline, as it turns out, comes in clusters in sedimentary layers. It holds aquifer and is not magma-safe.
Magmaline is not found in the earth. You need to kill a Pale Rider in order to get one. They can be found in the magma sea and in the third caverns, and are !!fun!!.
Two new metals, Aeresium and Lunanium. The former is a semi-dense, magma-safe metal that can be used for constructions, while Lunanium is not magma-safe, but is very dense and is weapons-grade. Their ores, Aeresiumite and Lunaniumite, can be found in igneous and sedimentary rock, respectively. Aeresiumite is also found in alluvial stone.
Lots of new soils, using the new soil template. I couldn't be arsed to figure out clay, so no clay for you. You do get a new kind of sand (Red sand, available everywhere but the oceans), two new kinds of dirt (brown dirt and blue dirt, the latter of which is Aquifer-ready), and two kinds of ooze (Black ooze and blue ooze, both of which are oceanic soil, and the blue ooze is aquifer-enabled.)
New stones! Horichoko is a generic magma-safe rock that shows up in sedimentary clusters--pretty much its only purpose is to make oxyline slightly less common. Everything else is layer stones. We have Tetraline and Leylite, both igneous intrusive; Polynzite, igneous extrusive; Azurine and Kazurot, both sedimentary; and Zhorale, Nechetite, and Chaosine, all metamorphic. Some of them have interesting properties: Nechetite and Azurine are not magma-safe, but have a lower colddam point. Tetraline and Polynzite both have much higher melting points, and Leylite can never melt, boil, burn, or freeze. Chaosine has rather ominous values for everything and is now the material used for hollow tubes, and Nechetite.... well, I'm quite literally including it solely to see if metamorphic, aquifer stone will flood caverns. Mwehehehehe..... Turns out, yes, aquifer metamorphic stone does flood the caverns, but it also rapes your FPS, so I took that out.
I'm gonna redownload the latest update, merge my raws with it, add the reactions required for Iridium Processing to all civilized, metal-using races, and then upload.
EDIT:Remind me, can halflings work metal in fort mode without PERMITTED_JOB:FURNACE_OPERATOR ? Cause if I give them access to iridium smelting at all, I'm afraid they might start making iridium things if I give them the permitted reactions. You can take iridium items on embark, but they're ludicrously expensive. It's better just not to.