An update. I've got reactions set up for the experimental materials workshop to refine cobalt, palladium, and neodymium. You guys are already familiar with cobaltite, but neodymium and palladium required new ores. Neodymium is refined from monazite, which is found in frequent small clusters in alluvial layers. Palladium is a little harder to come by - its mineral, cooperite, can be found in in small clusters across any igneous layer, but isn't very common. Cooperite can also be smelted at a smelter for a 50% chance of a platinum bar, and the reaction to refine palladium also has a chance of producing a platinum bar in addition to the palladium bar.
Because these new metals will play an important role in tier 3's advanced alchemy lab, a "search for trace metals" reaction has also been added to the experimental materials workshop, which takes a few stones and has a small (3-6%) chance of yielding one of these metal bars. That sounds very low, but with all the stone you surely have lying around, you should be able to get a steady, slow supply of these metals, even on maps where they aren't found. You can also request the ores and bars from the Dwarven caravan.
Neodymium will be used in the construction of the magnetic dart launcher and a few other new components. Cobalt can be used for advanced mechanisms and precision tools, and will see some more uses down the road. Palladium will be used almost exclusively for catalytic converters, which will be an optional "safety" component of some new reactions - as in, you can do the reaction with or without them, but having them present removes the possibility for some new alchemical disasters. Or you can be cheap, put some dwarven life on the line, and do it without them. It's totally up to you.
--
In case you're wondering how the development process is looking, it's hitting its usual sidetracks. I was playing around with some new concepts for zingers. First, I wanted to bring pyrophoric zingers back, if possible, but I needed a way of making them more effective. So the idea hit me to set their blood ("napalm") to an obscene temperature, which should result in them causing the desired wounds, but also would result in a bunch of flaming hot napalm all over the place afterwards, so I need to find an effective way to get rid of it (besides magma and/or walls). If the blood was set to a temperature where it would ignite, maybe I could make it burn off, but I need to do some playing around to see how contaminants respond to temperature to see if that will work.
Which then got me thinking... I could very easily make acid zingers, with a contact blistering and bruising and pain effect added to their blood, and I wouldn't have to clean that up because it's acid and you'd have to set up a disposal system on your own, but since it doesn't rely on high temperatures, this could be done with water. So now, instead of the advanced alchemy lab, I'm here writing and testing castes for zingers against walruses.
About an hour after that acid zinger idea, I went out for a bit and took a bath when I came home, when the idea hit me for an even more bizarre and hilarious zinger caste. Unfortunately, this one requires the CE_BODY_TRANSFORMATION token, which isn't in game yet, but it basically works by utilizing two castes. Caste #1, the "subcritical zinger," is a regular zinger, but doesn't explode on death. Instead, its blood carries a syndrome that only affects its caste. When something hits it, provided it isn't a one-hit kill, it gets its own blood all over itself, transforming it into a caste #2 (pop ratio 0, so it only occurs this way) "supercritical zinger," which enrages, attacks, and kills itself with an UNDIRECTED_DUST attack, throwing around a contaminant and knocking everything around like a cave-in. If it works, it will be absolutely hilarious, but we'll have to wait and see.
So yeah, that's been my day. Refine reactions, minerals, and playing around with new ways to make zingers blow themselves up. Oh, and testing an easter egg plant. Pretty productive, if you ask me.