Make your own pyramid salt crystals | Hacker News Reader

Make your own pyramid salt crystals

crystalverse.com

275 pointsklyrs30 comments

This website is what I want the internet to be. Information like this is such a treat, and I would have gone crazy for it as a kid (and I still do). I used to search high and low for books containing these kinds of guides, and it makes me happy to see it online.

I've got alum on order. My kid isn't old enough to do this one unsupervised, but this is our plan for next weekend.

Where can I get it?

Try a shaving supplies website, I think.

I got some years ago from ebay.

I found some food grade stuff, there's probably a reseller near you. Apparently it's used for pickling?

https://www.mccormick.com/spices-and-flavors/herbs-and-spice...

Yes, for sure. At least in the US, it will be in the spice aisle at your local generic grocery store (Safeway, Kroger, Walmart, Meijer, etc), although keep in mind that it is a very small container - on a cost-per-weight basis you are going to get a much better deal somewhere else.

That’s true regarding cost, but I’ve had the same little container for about 8 years now. I rarely need it, and I generally need a small amount. So it might not be too important to get more for less.

And you’re also right about where to get it. Mine was near the pickling spices in the spice aisle of a supermarket.

  > But I did find a study published in the World Salt Symposium where researchers successfully grew pyramid salt from waste salt water in large, steel crystallizers.

Wow, I never knew that there was an entire symposium dedicated to salt.

From https://www.bolton-menk.com/salt-symposium/:

  This event celebrates the optimization of salt use to improve community sustainability and protect vital freshwater systems and infrastructure.
  The Salt Symposium brings together leaders from diverse economic sectors to learn about the impacts of chloride and reduction methods. Professionals from across the world will share their expertise on current research initiatives including water softening, wastewater, fertilizer, snow and ice management, and more.

Also 484 pages of the pretty dense but readable, Salt by Mark Kurlansky

Seconded

Another recent salt submission: https://news.ycombinator.com/item?id=37786245

Yep, that's what tripped me down the rabbit hole I found this article in.

Have you ever heard of the Royal society for putting things on top of other things?

The YouTube channel Alex (FrenchGuyCooking) made some nice flakey salt in this video: https://youtu.be/eN6U58LzyHg It's a similar process, but he uses coarse sea salt without any alum or other additives. The results are less uniform, but probably better for human consumption.

> The key is to add an ingredient called potassium alum. Alum calms the surface and helps the pyramids form.

Does anyone know of scientific article where I can read more about this? I've never heard of alum's water calming abilities.

Not an expert, but probably in relation to this[1]:

> In water, most of the particles are negative charged, to neutralize the charge a positive ion (cation) may be used as a coagulant. Potassium hydroxide contributes a mono-valent ion, K+. Calcium hydroxide gives a divalent ion, Ca2+. Aluminum coagulants give trivalent aluminum ions, Al3+. According to Schultz in 1882 and Hardy in 1900, higher the charge of cation, more effective is charge neutralization.

This charge would be present at the surface[2] if not dealt with via the alum, and I imagine that could disrupt the crystallization process happening there.

[1] https://link.springer.com/article/10.1007/s13201-018-0662-5 [2] https://en.m.wikipedia.org/wiki/Surface_charge

An excellent question, it seems way outside my high school chemistry knowledge that you could calm water with a tiny amount of anything, be it alum or otherwise.

>"6. Monster pyramids

The first pyramid salt crystal that grew from this solution was an absolute beast. The humongous head was covered with all sorts of intricate formations that reminded me of bismuth crystals."

That's a very interesting observation!

I'm wondering in all of Chemistry -- are there other possible crystal formations that look like Bismuth or specific Bismuth-looking pyramid salt crystals?

Also, could we take molten Bismuth -- and somehow grow a pyramid shaped crystal out of it? If so how? If not, why not?

Anyway, great article!

The salt itself crystallizes as cubes.

https://en.wikipedia.org/wiki/Halite

> However, I would discourage you from eating pyramid salt grown with this method regularly. I’m no dietician, and it’s best to look for an expert before adding something new to your diet.

I thought these crystals are 3D printed at first judging by the layered look.

Resin 3D printing is kind of this at a finer resolution.

The article says ‘Add 0.5 g of alum per 500 mL of salt solution.’ but in the gif demonstrating the difference, it’s 0.5 g of alum per 100 mL of salt solution.

A photo caption also says, "No need to measure – just drop a few pea-sized pieces of alum/two pinches of alum powder into the solution and let it dissolve.", so the exact ratio is unimportant.

Has anyone tried doing this with Bismuth?

Bismuth crystals can also be grown at low temperature, so maybe they can be shape controlled as well.

Yeah of course, you can even make it from pepto bismol tablets from what I remember reading [1] [2]

[1] https://www.wikihow.com/Make-Bismuth-Crystals

[2] https://www.thoughtco.com/bismuth-metal-pepto-bismol-antacid...

I think the surface of the melt will oxidize so you might need to cover it with inert gas but something like this might be possible. One issue is that the crystals might want to melt if they grow downwards into the molten liquid. I think the temperature gradients might be really important here.

> I think the temperature gradients might be really important here.

Hm, I'm trying to think of ways to maintain an even gradient without unduly stirring up the liquid metal.

Probably sealing the pot-o-bismuth inside another container, where the outer container's fluid is being stirred and circulated to minimize external gradients.

This is fantastic, bravo !

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