My daughter has this as an school assignment, with some implication that it is some sort of a contest, and we managed to grow quite a few of similar quality to the seed crystals on the site in 4 days, which was the original (poorly thought IMO) deadline.
The trouble is that no one else was able or cared to do it so fast, so the deadline has been slipping for a couple weeks now, with our best crystals going to school and back a few times, getting scratches and broken bits instead of nicely growing undisturbed.
A bit discouraging. I'm now remembering how frustrating was for me to take school related things too seriously and discover you cared more than your teachers when I was her age.
When I was an organic chemist, growing crystals was of paramount importance for certain structure determinations using X-ray crystallography (to answer "did I really prepare what I think I prepared?")<p>With sensitive compounds, sometimes you can't just let things evaporate. Also as the article states, weather conditions might mess you up.
IMO the coolest trick we had to solve this was osmosis of an anti-solvent into a saturated solution.<p>A small sealed container with a saturated solution of your compound/salt is punctured, and put in a bigger sealed container containing a worse but miscible solvent for the compound under study. Slow diffusion into the inner container causes very reproducible crystal growth, as long as you can control the temperature.
The rest of the content on this website is simply amazing. I'm so glad stuff like this is still out there on the internet. Nothing clickbaity or exploitative, just really detailed instructional knowledge on an interesting niche subject.<p>Check out his copper sulfate crystals if you want something really visually impressive: <a href="https://crystalverse.com/best-way-to-grow-copper-sulfate-crystals/" rel="nofollow">https://crystalverse.com/best-way-to-grow-copper-sulfate-cry...</a>
Calcium tartrate is a great high speed introduction to crystal growing because it is very forgiving and "magical." You can get ~millimeter size crystals in seconds. Then once you're hooked you can try growing crystals that require more patience/technique. If you ever saw the demonstration of lead (II) iodide precipitating from solution [1], this demonstration looks similar except that the crystals are sparkly and colorless instead of sparkly and golden.<p>You'll need potassium hydrogen tartrate (cream of tartar), sodium hydrogen carbonate (baking soda), and calcium chloride (sold as DampRid or Pickle Crisp).<p>Add a spoon full of baking soda and a spoon full of cream of tartar to a glass of distilled water. They should fizz together as the baking soda neutralizes the acidity of the cream of tartar, releasing CO2. This is what you want, since the mixed neutral salt of tartaric acid is more soluble in water. Stir and wait for the fizzing to die down, then gradually stir in small portions of more cream of tartar until the additions stop dissolving. Let the solids settle in the glass.<p>Meanwhile, dissolve a spoon full of calcium chloride in a second glass of water. It should dissolve readily with a bit of stirring.<p>Once residual solids have settled in glass one, decant the clear liquid into another glass.<p>Now pour the clear decanted liquid into the calcium chloride solution with stirring. Within seconds, you should see sparkling needles rain out of the solution. These are your crystals. The transition is especially striking in direct sunlight. The crystals can be saved and seem to remain stable in air regardless of ambient humidity.<p>I unfortunately have not seen this demonstration written down elsewhere so I can't offer a citation. I came to it by personal experience when I was on a crystal growing kick as a kid. (Though it may well have been written down somewhere that I have never come across.)<p>[1] Like in this video: <a href="https://www.youtube.com/watch?v=AO67MnZaAvQ" rel="nofollow">https://www.youtube.com/watch?v=AO67MnZaAvQ</a>
> Indeed, table salt is often used in kids’ experiments to demonstrate crystallization. It’s a simple activity, but the results are disappointing.<p>I remember this was one of the things I tried countless times as a kid. It never worked - the books showed these nice, clear crystals but all I ever got was a crust of dried salt and maybe one tiny crystal a few mm across.<p>I'm sure most of those "science for kids" book authors never tried a single one of their experiments.
I used to enjoy growing crystals when I was a kid. It's a good indoor activity for the winter.<p>Plain white sugar is also interesting. Alum (used to make pickles, can often be found in the herb and spice aisle at the store) makes neat crystals.<p>If your kids are old enough to be trusted not to eat the experiments, copper sulfate (used to kill roots that are growing into sewer lines) makes beautiful crystals. It can be found at Home Depot-type stores.<p>Edit: I see this author has a link to another article on growing copper sulfate crystals down at the bottom of this article. Recommended!
More discussion from original poster. <a href="https://www.reddit.com/r/mildlyinteresting/comments/qvxyjg/a_salt_crystal_i_grew_at_home/" rel="nofollow">https://www.reddit.com/r/mildlyinteresting/comments/qvxyjg/a...</a>
Crystallography, the study of crystals and the structures of their constituents, is fascinating. I work in a field where making crystals like this is so tough that people spend millions of dollars on robots and reagents that just sit around trying every possible combination of temperature, concentration, and other parameters, just to make crystals with high enough quality to do structure determination.<p>Some crystals just never form. I know folks who spent 7 years trying to get their protein to crystallize and left grad school with a masters degree instead of a PhD because they failed, no fault of their own.
Looks really good. My three chemicals for crystal growing are<p>ADP<p><a href="https://en.wikipedia.org/wiki/Ammonium_dihydrogen_phosphate" rel="nofollow">https://en.wikipedia.org/wiki/Ammonium_dihydrogen_phosphate</a><p>and MKP<p><a href="https://en.wikipedia.org/wiki/Monopotassium_phosphate" rel="nofollow">https://en.wikipedia.org/wiki/Monopotassium_phosphate</a><p>and Alum<p><a href="https://en.wikipedia.org/wiki/Potassium_alum" rel="nofollow">https://en.wikipedia.org/wiki/Potassium_alum</a><p>but probably table salt is cheaper..
There's also "salt pyramids" [1] which are desired in Culinary field for their look and texture. Be pretty cool if there was a way to grow a transparent salt-pyramid.<p>[1] <a href="https://www.youtube.com/watch?v=FVEZuzEHwQk" rel="nofollow">https://www.youtube.com/watch?v=FVEZuzEHwQk</a>
Wow thanks for sharing this. Have always wanted to do this ever since I read the first blog on growing crystals [big time procrastination there]. Please share your experience and steps if any for other salts. I am super interested in the blue of Copper sulphate.
These are beautiful. Seems that a possible solution to the problem outlined at the end of the post (they are not quite cubical, but flat) would be to gently flip them a few times during the months they are growing.
Welp, this is a silly project that I have no choice but to try. Looks straightforward and rewarding with a nifty end result.<p>This is a content-less comment but... great article, thank you for submitting.
Once, I accidentally grew a bed of salt crystals in a plastic tumbler left on a windowsill. Sadly I can't find the photos but they were closer to rectangular and clearer than the "bad" examples mentioned in this post. Diameters reached ~500mm on the large ones. Was I vastly luckier than I realized at the time, or is it all a bit easier to get right if you're not aiming for completely freestanding crystals (vs. a bed)?
This makes me curious, and I googled a bit trying to find how large you can grow these transparent, cubical crystals.<p>Largest I was able to find was about 2cm to a side, maybe a bit less.. Is there any fundamental reason they don't get bigger than this/lose transparency and form as they grow larger, or is it more that no-one bothered doing growing them larger than that?
This is a really cool write up and really intrigues me, on the topic of crystals. I admittedly have very little knowledge or frame of reference on the topic. But there is something very cool about the idea that you can ‘grow’ crystals, like they are little house plants, or that they are like little living creatures or something.
I've never seen this before and wonder how stable/fragile are those crystals? Are they very touch-sensitive or can you carry them around easily in your pocket?