While I had been working on the cryogenics facility, I had thought about methods for growing fluorite crystals from time to time. So, I resumed my research with renewed vigor. However, that vigor ran out fairly quickly. My first few attempts involved attempting to partially heat the top of the molten fluorite, and slowly cool it down to grow the crystal. All of those attempts still failed. Too many new nucleation points, or simply the production of a glass were the results of those experiments.
So, after a month of attempts, I tried a different approach. Instead of moving the heat source, I instead tried lowering the vat of liquid fluorite. That seemed to initially have the same issues as before, but I persisted and tried tinkering with the process. I found that if I lowered it too quickly, it'd form a glass, and as I slowed down the rate that the vat was lowered, I started getting nucleation of crystals. The problem was that I was getting multiple crystals all over the vat, and they remained fairly small, eventually getting encased in glass themselves.
I changed out the vat for a vat made of polished steel, and changed up my entire apparatus. Instead of manually lowering the vat, which seemed to always result in it getting lowered too quickly, I changed it to be gear driven, with a gravity driven escapement mechanism to very slowly lower the vat away from the heat. The first few tests were slightly more successful than the first, but I was still having the issue of too many nucleation points.
After another month of testing in total, I changed the vat design again, this time having the bottom of the vat shaped the same as a singular fluorite crystal. My hope being that the lowest point, which would be furthest from the heat source, would also provide the starting for nucleation, and that crystal would be where all the new fluorite deposits.
This method had mixed, but improving results. Intermediate results would still have too much nucleation occurring, with new crystals growing off the sides of the vat, or even on the face of another crystal. I decided then that I still had a few too many variables to control to properly form this process. For one, I was still attempting to heat the vat using charcoal, so the temperature was likely fluctuating a lot near the top of the vat. A second issue was likely that the whole process was still exposed to air.
So, I took a month and a half attempting to alleviate both of those issues. While I'd love to use a fixed rate hydrogen fire to generate the heat for this process, we don't really generate enough heat for the vat I've been using for testing. We can, however, improve the consistency of the heat in a different way. If we used standardized charcoal pellets over raw charcoal, the general temperature fluctuations should be smaller with the more consistent fuel source. Of course, producing charcoal pellets was easier said than done.
First the charcoal needed to be pulverized into a powder, which was fairly easy with our given technology. However, the process of compressing and cutting pellets was a little tricky to rediscover, and I got fairly lucky. I designed the pellet machine to compress powder through small die, like how we make wire. However, since I want regular pellets, I wanted the cutting process and the compression process automated and tied together mechanically, so they'll always work at the same pace.
Ultimately, I lucked out in that I just so happened to time the passage of the blade which knocks the pellets off with when the compressive roller would finish forcing powder through the die. If I hadn't timed it like that, the machine would have output a lot of failed pellets in addition to a few good ones, and I'd probably have wasted a day or two figuring out what was wrong. After hooking the pellet press up to a small windmill, I then tasked some goblins with making charcoal pellets from now on. Besides being potentially useful to me, the stable burn of pellets will probably also be useful in some precision metalworking which the blacksmiths might want to do.
I also did some design work on how the heating element is fueled, to keep the heat source balanced. Thanks to having already worked on the pelletizer, I already had a good idea of how to make sure our fuel source was evenly distributed, and I designed a rotating pellet source and scoop to constantly rotate above the fire, pouring new pellets on slowly, while also scooping excess pellets off that might have piled too high.
The vat itself was fitted with a stone lid, with a stone shaping vacuum valve, so I could attempt to remove any potential impurities that might occur from that end. After finishing this new design, I've realized that I only have a little under two months left before I need to start training goblins on cryogenics to get that facility running more permanently. Which basically means if this new design doesn't work then I'll have to put artificial fluorite on hold again for a few seasons.
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Results seemed promising enough in the first real trial that I continued my attempts. I say first real trial because there were multiple mechanical hiccups during the first few days of tests. Seven days in, I had my first real taste of success, albeit a bit lackluster. The crystal seed at the bottom did grow to be the largest crystal in the vat, but there were still numerous other crystals forming throughout the vat's walls. That trial growth ran over 12 hours in total. The largest crystal still had off-growths on it as well, so I slowed the growth process down further by inserting extra gears into the escapement mechanism.
After multiple trials of increasing duration spanning 25 days in total and some upgrades to the escapement mechanism, I finally succeeded as much as I think I'll be able to with our current technology. There were still some secondary crystals growing on the vat walls, but the main fluorite crystal in the center of the vat was the bulk of the mass. The main crystal was practically flawless, and because it was grown on the surface, it was still extremely hot to the touch.
The first artificial fluorite crystal that showed success was practically colorless, but had a very faint orange tinge, a remnant of what little of the natural impurity was left after melt cycling it so many times. The crystal also produced the faintest amount of heat still. The largest natural fluorite that I had pulled from the limited amount I mined was about 4 inches along it's diagonal. By comparison, this crystal was about twice that height at just over 8 inches.
While an 8-inch octahedron is nice, I'd like to grow larger ones in the future, now that I know that it's possible to grow them artificially. It's also important that I handle the crystals as little as possible as we melt them down to reform them, as to attempt to keep as much of the natural inclusion material as possible. For research purposes, we actually want to do the opposite, and heavily process and filter until we have naturally pure fluorite, which we can then attempt to add inclusions into.
In retrospect, I should have probably been wary of the transparent fluorite, in case it too produced any unknown magical effects. Though by the time I realized that, I'd been handling this new crystal for a few days while experiencing no symptoms. With just over a month left, I want to grow a colored fluorite crystal this size, and test some plates cut from that crystal to see how they perform.
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I ended up having to mine more fluorite to make a good batch of molten fluorite material. That being the case, I decided to mine enough for a few batches of crystal growth, just in case I had any other sudden ideas while I worked. While I did successfully grow an 8-inch tinted fluorite crystal, it's color was still slightly fainter than the natural crystals I had mined to make it. Since I grew it on the surface, with ambient mana about, it was actually quite hot to the touch even after it should have technically been cooled down.
Thankfully, fluorite is pretty soft, and I was able to easily cut an inch thick plate from the center, leaving me with a squarish plate measuring just over 5.5 inches per side. Then, I was left with two square pyramids each 3.5 inches tall. While I could continue cutting the pyramids down, they could each be useful on their own as well, and the larger the crystal, the more efficiently it turns mana into its final product, so breaking it down further might be a waste.
After testing the plate, it still seems like crystals, or at least fluorite, rely pretty much entirely on volume for magical effectiveness. The plate, while only 1 inch thick, and 5.5 inches to a side, has nearly three times the volume of a 4-inch fluorite crystal, and seems to produce an appropriate amount of heat that I'd expect for that volume. The difference, however, is that it has a much shorter distance to it's center from the surface, meaning it can dissipate heat generated across it's volume faster, making it much more useful for industrial purposes.
Although I don't have proof of it yet, I also suspect it can probably intake mana more effectively, given it has a higher surface area to volume ratio. While a small crystal would have an even larger surface to volume ratio than the plate would, small crystals suffer from being unable to produce much of a magical effect, losing any advantage they might have had.
After only nine days of work though, I recalled that I should probably go do some levelling again before the new year begins so I went and did thirteen days worth. Next, I'll need to train the new goblins on how to operate the cryogenics facility. After those goblins are trained, and I'm confident in their abilities, I plan on trying to design a much larger fluorite crystal growing vat. Since the 8-inch crystal was already quite hot on the surface, I'll actually need a decently sized underground facility to do this work in.
Level: 74
HP: 3589/3589
MP: 1893/1893
Traits: Mana Affinity, Earth Manipulation, Improved Dexterity, Heat Resistance, Partial Sleep
Magic: Improved Stone Shaping, Tectonic Sense, Improved Earth Spike, Thermal Hands, Pulverize