Why salt crystals grow as pyramids (sometimes)

Some explanations are so remarkably simply that I never would've thought of them.

I've heard of hopper crystals in bismuth for years. I always assumed that they were studied by a scientist named Hopper. In this video, Adam Ragusea explains that they're actually called hopper crystals (not Hopper crystals) because they resemble the shape of a hopper that feeds ingredients into a production line.

And that's just the surface level of new knowledge that I got from this video. Adam spends much more time trying to explain why making hopper crystals of salt - the ones he shows and that I have in my cabinets at home as Maldon salt - is hard to do. Apparently they only form in super-saturated salt solutions and then only stay hopper-shaped pyramids until they either bump into other crystals to form a raft or get heavy enough to sink to the bottom of the solution and in-fill with more salt.

If only they could get them to grow in space - as an International Space Station experiment shown in the video recounts...

The Bismuthsmith

I've made bismuth crystals once or twice. I'm no Todd Bollenbaugh or anything, but I'm getting there.

Even Todd, however, isn't any sort of Bismuthsmith. He - actually, his name is Kyle Lauzon according to his Facebook page - seems to be an absolute bismuth master.

He makes tons of gorgeous hopper crystals and casts loads of varied figures.

...and he seems able to control the oxidation rate well enough that he can get consistent coloration from the oxides.

If you check out some of his live stream videos - through which he apparently sells his wares at discounted prices, I'm not sure how that works - you'll see that all the figures of a certain type have very similar coloration. He's obviously not doing that randomly.

And he seems able to control the color on the hopper crystals, too, because you can order specific colors.

I'm impressed, man...really impressed.