I discovered a way to grow transparent sodium chloride crystals at home. Here’s how.
Growing sodium chloride crystals
Sodium chloride, or table salt, has a cubic crystal structure. But the salt we use for cooking normally looks more like sand.
Indeed, table salt is often used in kids’ experiments to demonstrate crystallization. It’s a simple activity, but the results are disappointing. Many tutorials online make it look far easier than it actually is.
This is because sodium chloride crystals are very sensitive. Temperature differences cause imperfections. It also crystallizes easily on dust particles, growing misshapen clusters, hopper crystals and dry crust.
However, being as stubborn as these crystals, I have tried multiple times to grow them over the past 3 years. Eventually, I discovered a technique to grow large, high quality sodium chloride crystals, and I want to share it with you.
It’s a simple procedure that you can follow at home. This guide might seem long, but the lower half is about how to adjust the steps to grow more interesting and unique salt crystals.
To start, you’ll need:
- Uniodized table salt
- A large pot for heating water
- A spoon for stirring
- A filter funnel
- Filter papers/tissue paper
- A large jar
- A flat dish
- Some small, flat containers
Some people have told me it’s hard to get uniodized table salt. If so, you can also use sea salt with no additives (iodine, anticaking agents). I’ve tried it, and the results are the same.After that, we need to prepare our solution.
Preparing a saturated salt solution
Sodium chloride has a solubility of 36 g/100 ml of water at room temperature. When you dissolve this much salt into water, it becomes a saturated salt solution.
Once water evaporates, the extra salt has to come out of solution, forming salt crystals. Our goal is to control this process – to make the crystals that grow as beautiful as possible.
But first, we need to make our saturated salt solution.
Prepare a pot of hot water, and add 40 g of salt for every 100 ml of water. Stir until most of the salt has dissolved. It’s okay if some salt is left over at the bottom.
Keep heating until you see small, white salt flakes start to form on the surface of the solution. Let the solution cool, close the lid and leave it for a day.
Keep heating until you see small white flakes appearing on the surface of the solution.
Note: If you’re using a metal pot, it’s best to pour the solution into a plastic/glass container once it cools. The saturated salt solution can damage the pot if left inside for too long.
After letting the solution sit for a day, it should have stabilized. There should be some excess salt and bits of yellow impurities inside. We don’t want that.
So, using a filter funnel and some filter papers/coffee filter/tissue paper, filter the solution into a large jar. This will be our stock of clean, perfectly saturated solution, which we’ll use to grow good crystals. Recycle or discard the leftover salt.
Growing a seed crystal
After we have our saturated solution, we still need to grow a seed crystal. A seed crystal is a tiny, perfect sodium chloride crystal that we can then use to grow a bigger crystal.
It’s easy to grow seed crystals. Just pour 50 ml of the solution you recently prepared into a flat dish. You don’t need to fill the dish; the solution just needs to be around 1 cm deep.
I’m using a petri dish, but any non-metal container will do.
Having done that, leave the dish in an undisturbed area for 1-2 days. You can place it in a cool cupboard, on a rack or in the storeroom.
Since the solution inside the dish is saturated, it shouldn’t take long for small sodium chloride crystals to form. They look like tiny, transparent cubes.
After 2 days, this is what my dish looks like.
If the dish looks like this instead:
It means the solution evaporated too quickly. Either the weather was too hot or it was exposed to air movement (like wind or the fan). Try again by placing it in a more sheltered area.
Great. We now have our seed crystals.
Try to look for a decently sized square crystal that is completely transparent. That will be your seed crystal.
Growing big sodium chloride crystals
Now, we can start growing our main crystal. For most compounds, it’s easier to grow the crystal by tying it to a string and hanging it in solution. But not sodium chloride.
Because sodium chloride crystals are so sensitive, any interruption to its growth (like tying it to a string) will almost certainly cause defects to form.
To minimize interruption, it’s best to grow it at the bottom of a container – one with an extremely low rate of evaporation. Based on my experience, aim for very small containers with flat bottoms.
After trying out teeny beakers, jam jars, plastic sauce containers… I found that makeup jar lids worked best. Of course, it’s entirely up to you.
Now, transfer a little solution to the container of your choice, making sure it is dry beforehand. Select a seed crystal. With a pair of tweezers, very gently transfer the seed crystal from the dish to your new container.
The makeup jar lid is in the middle. I first transferred some solution there, and then moved a small seed crystal from the dish, placing it right in the center of the makeup jar lid.
Move the container to somewhere sheltered. Again, storerooms/basements/cool cupboards are good choices.
This setup is the best I’ve found so far, but it still doesn’t guarantee a perfect crystal.
From left to right – how increasing the rate of evaporation decreases crystal clarity.
So, to further provide a stable environment, make sure the surface of the solution is not exposed to air movement. This is an easy fix. Just cover the setup with another container.
You can cover the setup any way you like.
This greatly helps the transparency of the final crystal. After that, just leave them there. Within a day or two, the crystal inside the dish should look like one of the following:
- Perfect conditions. The crystal has started growing nicely. Good job!
- Salt dust formed around your main crystal. You likely scratched the crystal by accident while transferring it.
- The crystal grew too quickly, thus turning opaque. Either the weather was too hot or the humidity too low.
- The salt crystal started to dissolve. The solution was not saturated enough. Either the humidity was too high or your container was a little wet when you added the solution.
It’s okay if accidents happen. If the crystal looks like picture 2, it means you have to select another seed crystal and try again.
If it looks like picture 3 or 4, let it grow anyway. The final crystal will not be perfect, but as you’ll see, it can still grow in a very interesting way.
Now, all you need to do is to wait. Depending on the conditions, it will probably double in size in a week and reach 1×1 cm in a month. This might seem like a long time, but to crystal growers and chemists, it is a terrific accomplishment.
As mentioned, a clear crystal turns cloudy when it grows too fast. However, the bigger the crystal, the more tolerant it is to such changes. This means you can transfer your bigger crystals to a larger dish to provide more room for them to grow:
A transfer is optional, of course. There’s a risk the crystal will get scratched, cloud or dissolve during the transfer. A larger container also gives more opportunities for smaller crystals to stick to your main crystal.
You can stop growing them when you think they are big enough. Remove it with tweezers, then dry with a filter paper/tissue. Don’t leave it on the paper for too long – it will get stuck there.
And… you’re done!
Take it outside to admire its crisp edges, take some photos and give yourself a pat on the back. Show off your salt cubes to your friends.
Then, keep it in a closed container. Sodium chloride crystals are stable, which means they require no special storage.
Interesting sodium chloride crystals
There are many factors affecting sodium chloride crystal growth. The ones you grow might look completely different from mine. Here are some interesting specimens, and how you can achieve them.
- Growing slow vs growing fast
- Crystal stars
- White cubes
- Ghost crystals
- Salt pyramids
- Using iodized salt
- Other impurities
- Crystal clusters
Growing slow vs growing fast
Crystal quality depends a lot on the rate of growth. The following pictures show crystals grown with a low, medium and high rate of evaporation respectively.
Good specimens take time and patience. Don’t get discouraged though; the most important thing is to enjoy the process along the way. In fact, the crooked crystal in the top left of the 3rd pic is my very first sodium chloride crystal!
Sometimes, a crystal turns cloudy at first, but as it grows, the outer layers become transparent, forming a nice coating. The result looks like this:
You can achieve this by growing the crystal in a larger container right from the beginning – without the cover to limit evaporation.
Be wary though. The process will become a lot more unpredictable. Tiny crystals like to form and given enough time, they might stick to your main crystal. But with the right conditions and some luck, you’ll get your crystal star.
White cubes are basically crystal stars grown at an even faster rate. It’s a balancing act – if the evaporation becomes just a bit faster, or some random crystals decide to form on a speck of dust, everything will turn into a white clump.
If you want to recreate this, follow the procedure for crystal stars on a hot day.
This particular crystal looks more like a cube because I flipped it on its side when transferring to a new container. Normally, the new side immediately begins to cloud up due to a change in growth rate, but since the crystal was already white to begin with, it turned out looking great.
During crystal growth, the weather might suddenly get very hot – or it might rain a lot. These conditions will make the crystal cloud up, or dissolve respectively. Then, if the conditions return to normal after a few days, transparent growth resumes.
But this interruption causes the crystal to contain a flaw in the middle. Sometimes, this flaw can be quite unique, like a hologram trapped in glass.
Notice the “star” inside the crystal on the right.
When seed crystals grow, not all of them look like cubes. Sometimes, a seed crystal lands on its vertex, forming what looks like a pyramid.
If you let it grow, this is what you’ll get:
A regular salt crystal (left) compared to a salt pyramid (right).
Due to the strange way they form, salt pyramids are stuck to the bottom of the dish. They cannot be moved – attempting it will cause salt dust to form, failing the run. So it must form, grow and be harvested from the same container.
Note that these salt pyramids are not the same as hopper crystals that form on the surface of a quickly evaporating solution. Those look like hollow, inverted pyramids that have a staircase pattern and grow in a very different way. Although they form occasionally in nature, there is very little information on how to grow them online.
Edit (Dec 2021): I have discovered a way to grow these hollow pyramids. I’ll work on the procedure, and hopefully write a guide like this one soon.
Edit (Aug 2022): It took longer than expected. I’ll publish the article and share my findings in about a month. It’s gonna be awesome 🙂
Edit (Sep 2022): It’s out! Here’s how to make pyramid salt crystals at home.
Hopper salt crystal pyramids that I managed to grow. These are very different from the crystals that are the subject of this guide.
Using iodized salt
Iodized salt is not recommended for growing sodium chloride crystals because it messes up the crystallization process. This makes it hard for single crystals to form.
The crystal below was grown with iodized salt, following the same procedure.
If you think it’s beautiful, by all means give it a try.
Besides iodized salt, other impurities in solution can also affect crystal growth.
Rock salt and sea salt might give slightly different results, because they contain traces of other minerals. But in general, they work. Make sure the sea salt you use does not contain anticaking agents.
Adding urea to the salt solution causes the crystals to grow into octahedrons. Surprisingly, there are no pictures of macroscopic ones online. An acidic solution encourages the formation of thin, needle-like crystals.
Veteran crystal grower Dmishin found that adding ferric chloride to the salt solution makes the crystals behave better and become more transparent, at the cost of yellower crystals. For a more detailed explanation, check out his article here.
If you don’t want to grow single transparent crystals, but want a more natural looking cluster of salt crystals instead, good news. It’s much easier. This article explains it all.
Although sodium chloride theoretically crystallizes as cubes, the crystals grown with my procedure look a little flatter on the side facing up. This is a limitation to growing them on the bottom of the container, because each crystal face grows at a different rate.
To prevent this, we need to suspend the crystal in solution instead, which brings other challenges. The hanging method currently doesn’t give me good crystals, but I look forward to progress there. If you’ve gotten good results, please share them with me.
Edit (Aug 2022): I am working on the hanging technique to get nice symmetrical cubes. Half of my attempts failed, the other half are progressing well. Stay tuned for updates.
In short, sodium chloride crystals can be very tricky to grow. But with the right procedure, anyone can grow salt cubes at home. Some factors affecting growth like the weather might be out of our control, and we might not get a perfect crystal, but what we end up with might be just as beautiful.
That’s all for this guide. If you have any questions, feel free to ask me in the comments below.
And if you would like to see more crystal growing guides like this, consider subscribing to my newsletter. I’ll let you know about my latest discoveries.
In the meantime, why not check out my post on growing crystals from fertilizer.
This compound is common, non-toxic and forms stunning crystal clusters easily. Here’s how to grow them.
You can also grow huge Epsom salt crystals, which are one of the fastest growing crystals available.
Thank you for reading, and as always, happy growing.
Un poco loco
What should I do when my crystal won’t grow? It has been almost a month, and my crystal (sea salt) only grew to a few milimeters. I don’t actually know if it increased in size or not from the day I transferred the seed crystal, and the only changes that I have seen in the solution is the growth of many other smaller crystals.
It’s normal for your crystal not to grow sometimes. It can be due to the environment (not enough evaporation / possibly too humid) or because there are too many crystals competing with each other. Perhaps additional crystal seeds formed when you transferred the seed crystal – and so now there are many smaller crystals fighting for growth. You might want to try transferring your main crystal into another new container – and then covering the lid for a few days to discourage extra crystals from forming before reopening the lid. It will grow much faster this way.
Can crystals be recrystallized? As in, can you take the crystal out, dry it, and place it into a saturated solution to resume its growing?
Yes, all water soluble crystals can be recrystallized. In fact, growing crystals is all about recrystallization. We’re dissolving tiny crystal grains of salt into the water, and leaving it to evaporate, allowing bigger crystals to form.
You can take the crystal out and then resume growing it. But this interruption might cause some defects to form, so that the crystal is no longer so nice and clear. Some crystals handle this better than others; sodium chloride crystals are very sensitive to these changes, while monoammonium phosphate crystals fare much better.
Love the details and committment, great job!
Is there a method to move the crystals to the lid without scratching them?
Try using a dropper to suck up a drop of the solution, together with the tiny seed crystal. Then squeeze the dropper to transfer the drop to the lid.
Hey! Been checking out this blog for months, everything is so well-written and pretty. I think I finally wanna try making salt crystals! I had a couple questions though:
1. You mentioned in the single sugar crystal instructions that moving the seed crystal with a spoon keeps it from breaking off sugar dust, and mention here that you should be delicate in moving the salt seed— Would using a spoon be advisable here too?
2. Average humidity where I live is about 75%— Is this likely to interfere with crystal growth? Should I include a desiccant in the process while it’s growing?
(These ones are more for curiosity’s sake than anything else XD Unlikely to do these in my first time lol)
3. Would covering/uncovering the dish as it’s growing give you some control over star or ghost formation, if evaporation rate affects clarity? Or would it not be enough to affect it in any meaningful way?
4. Would food coloring change crystal color?
Once again, love the blog— Thanks for all the work you put into it!
Hello! Yay, I’m glad you’re interested.
1. Different crystals have different habits. Some crystals can be easily moved around without any issue, others can easily be messed up. But generally you’ll want to be delicate when handling them. Sugar crystal seeds can be moved using a spoon because they form and float on the surface of the thick syrupy solution. Meanwhile, salt crystals usually form at the bottom of the solution, so it’s not as convenient to scoop them up using a spoon. Hence, picking them up with tweezers is preferred.
2. My place also has 60-80% humidity, so you’re good to go! Don’t use a desiccant when growing crystals – it can speed up growth too much.
3. Yes, it does. To address my previous point, you can use a desiccant for this XD
4. The dye molecules in food coloring are mostly excluded from the crystal structure, because crystallization is a purification process. Therefore, even if you add a lot of food coloring, the resultant crystal will only have a faint tint. Of course, some dyes are more effective than others, and these usually work on the principle that they somehow get incorporated into the structure of the crystal. For example, normally transparent alum crystals are usually hard to color, but if you add amaranth dye, they turn stunningly red and grow into a different shape.
All the best!
How can I show my crystals I made something but can’t find what it is
Send me an email at email@example.com, and attach a file there.
Done sorry it took me so long T.T
Every time I transfer the seed crystal to another container to grow, it dissolves within a few minutes. Is there any way to fix this?
Make sure that the salt solution in the other container is saturated. Before putting your seed crystal instead, you can put a grain of regular salt inside first and wait a few hours to see whether it dissolves. If it doesn’t dissolve, then your seed crystal won’t dissolve too.
Can the liquid from the cleaning solution be recycled into the larger concentrated salt?
sorry, meant to say seed growing
Yes, of course. Make sure you don’t introduce any powdery salt grains into your larger solution though. This can be prevented by letting the seed growing solution sit for a week before transferring it.
Do you know what the effect is of anti caking agents?
They prevent the crystals from forming in their usual way. This makes the crystals less transparent and encourages them to grow in clumps instead of cubes.
Hey Chase, I am very glad to have met you on line, especially for growing rock salt.
Though I have got some transparent rock salt from nature, I will following your detailed guide to grow rock salt by myself.
Thank you so much!
Those are some beautiful crystals. Thanks for sharing!
But can you use iodized salt?
It’s not recommended, because the crystals will not be large and clear – instead they look like small white clusters.
Thanks for the informative article! Like other commenters, once I’ve transferred my crystal to a new container, more seed crystals start to grow inside the container. I was wondering if I should remove the new seed crystals (with tweezers), or if that would disturb the actual crystal’s growth?
Again, thank you for this awesome guide!
If the extra seed crystals do not touch the main crystal, you don’t have to do anything. This is natural and difficult to fully prevent. If they look like they’re going to stick to it already, either 1) blow them away with a dropper (using tweezers will cause even more seed crystals to form) or 2) transfer the main crystal to another new container.
Thank you for this amazing post!!! Understandable and neat, I want to start growing crystals as a hobby and yours is the most well written.
Also, how does humidity affect the crystal growth? I thought that lesser the humidity, better the crystal growth. But I’m assuming that’s not the case after reading this post.
Once again, thank you so mch
Happy to help 🙂 Higher humidity is better. But maintaining a stable humidity (and temperature) is more important.
This is really great and I’ve been trying it with my kids. One problem I’m running into is that when I select a seed crystal and move it to its own container, more seed crystals start growing, and there is even precipitation on the surface. Maybe my solution has impurities?
It’s perfectly normal for more small crystals to form in a new container, but if too many of them are forming, it’s because your solution is too saturated. You can wait a few days for the saturation to decrease. Or you can try adding a single drop of water to the dish. This should discourage excess crystals from forming.
Hi, I want try this but I have a question. When the seed is created how much and how often should I refill?
When the level of the solution is low enough that the seed crystal is about to be exposed. Since the setup is covered completely, this happens very rarely. I add a few drops of solution to my crystals once or twice every month.
I once found a crystal in a bad of “organic” salt from whole foods like this image above on the very right.
It was the weirdest thing. I think the bag got wet and it grew somehow.
Hey! This is a really great article! Your salt crystals are beautiful and I’m super excited to start growing my own.
By any chance, is there a way to make them more durable during the growing process or a type of protective coating I could use? I’m thinking of making them into earrings but I’m worried they will break or scratch too easily.
Also, do they have to be stored in a container or can they be left out?
It’s not possible to make them more durable during the growing process, because adding anything will disrupt the crystal growth. However, once you are done growing them, you can coat them with nail polish, use an acrylic spray or seal them in epoxy. You’re right that they will break and scratch easily. Also, they dissolve in water so that complicates making jewelry of any sort. In that case, epoxy is your best bet.
Hi !! I was so curious about the beautiful square crystals left at the bottom of the containers I used to make Chlorine dioxide. After I mix NaClO2 with the HCl , I collect the ClO2 gas in a container with water as it dissolves there. Then I leave the mix to dry and the result are those crystals.
As a kid I grew a lot of sugar crystals. A book from the library said I could suspend them in a high concentration of sugar plus gelatin. I used lime jello. It didn’t work. But suspending a salt crystal in 40% NaCl plus unflavored gelatin (Knox brand) might work. Maybe. Unless any contaminants inhibit/change growth. Well. It might be worth a shot.
Do you mean suspending them without a thread? This is a very interesting idea. One problem that might occur is that some of the gelatin gets included into the crystal, making it cloudy. I have seen this happen with gypsum crystals others grew. But who knows, maybe this is different. I’ll remember to get some gelatin. Thank you so much for sharing!
About how much fluid should be in the final container for growing the seed crystal into the actual crystal? Should it be filled to the brim? The tutorial just says to put some fluid into it and I just want to make sure that I do it right
The exact amount doesn’t matter. The level of the fluid should be high enough that it shouldn’t threaten to expose the surface of the growing crystal. A height of 1 cm should be sufficient.
I found a different method which seems to produce good crystals so far where I take a flat tray and put my seed crystals spaced evenly apart and I have it open to the air and I take some water in a cup with salt crystals that are not pure I’m using rock salt and so that solution will always be saturated but not super saturated and I take a sprayer and spray a mist on them once every few days and as crystals that are not the ones I want develop I transfer to a new tray and add more water and so far the results have been a little bit variable sometimes I end up with a bunch of new crystals and sometimes I have only the seed crystals staying there seems to depend on the temperature of my house which is not consistent and unfortunately being open to the air dust particles and stuff can fall in but it seems to do a very good job at making transparent crystals
That’s great! My procedure is only a starting point, and I’m super happy that you managed to find a technique that works for you 🙂
Maybe I’ll try out your method the next time I grow salt crystals too.
Thanks for the amazing guide. So far I have some good crystals slowly growing. Maybe you can help me with a slight conundrum I have :P.
I’m leaving for holidays for a couple of weeks and I don’t want to lose my beautifully growing crystals 🙁 Is it possible to stop growth completely, that is taking them out of the solution and drying them, and then restart it later?
Have you experimented with bringing the solution in and out of its saturation point periodically so produce interesting patterns?
It’s not a good idea to change the saturation of the solution manually. The risk that something will mess up is too big.
Here’s my suggestion. If you’re using the setup that I’m using, the crystal growing solution should be reasonably stable (as you covered the top to limit evaporation). Therefore, you should be able to leave the crystals growing over the holidays. Then when you come back, they should be much bigger!
Of course, there’s also the risk that something bad happens and you lose everything. As a safety precaution, you can harvest 30% of your crystals now, and hope for the best for the remaining 70%.
As for your last question, yes, interesting patterns sometimes form when the concentration of the solution fluctuates. Sometimes it’s bad, causing cloudy growth; sometimes it’s good, leading to interesting star like patterns on the interior of the crystals. It can even leave triangular pits that look like fractal patterns on the surface of the crystal. I’ve never done any of these on purpose, though I agree that it’s something worth experimenting about. But all these require careful monitoring, so if you try out these steps over the holidays, it’s more likely that the crystals will dissolve completely.
Good luck, and happy holidays!
Thank you for this excellent guide. Explains why my previous attempts did not work well at all. I gave up then, a few years ago. Muttering and grumbling about about false advertising with kits. Now I am starting again. No expensive kits needed!
feel free to cut this out if it is not appropriate for your site.
PS. found your site via a person commenting on Pleated Jeans.
That’s great. It’s certainly possible to grow great crystals with kits, but the instructions are often insufficient. Plus, most of the time, you can get the main ingredient inside the kit for far cheaper. Good luck!
What a great site! I will be doing this with my children! Thank you!
Hi! Thank you for the easy to follow instructions! One question though: I have my salt solution, and I have left it to sit for a day before filtering it. Is it okay to add food colouring at this stage?
Yup, feel free to do so. Note that the food coloring won’t color the crystal completely, it will just give it a slight tinge of color.
If its made of salt….is it edible?
Of course 🙂
lol i actually tasted one of the crystals of salt i made before, and it tastes exactly like salt
I wanted to grow crystals since childhood, but never got the method right and therefore never succeeded. Now that I’m 27 I decided to give it another try so thank you for the detailed tutorial!
However, I followed the tutorial exacty till the part where we grow seed crystals. My solution is there for 2 days already but it looks just like someone dropped a tiny amount of glitter in the water. I got it covered, but the air can flow out. Temp is around 21-22 celsius. I do not know what exactly is wrong.
Can you please advice?
Hey there. It’s not a big issue. There were probably too many nucleation points, causing thousands of tiny seed crystals to form instead of a few big, transparent ones. Maybe there was a bit of dust in the solution, or the solution was slightly saturated, or you accidentally caused some salt to enter the solution.
Anyway, to fix it, just add 1 mL of water to the salt solution. Filter it into a new container. Then, leave it in another dish to crystallize.
The purpose of the water is to bring the saturation down and to dissolve any tiny particles in the solution. Once no more tiny crystals are present, as you leave it to evaporate, bigger crystals should form. Of course, it will take some time for new crystals to appear (a week or so) but the new ones should be nicer. Good luck.
this is by far the best tutorial i have found. do i need to preserve these? if so, will clear spray work?
Yay, thanks! Normally you don’t need to do anything special to preserve them. If your place is very humid, just keep them with in a closed container with a bag of silica gel.
If I made a sugar crystal instead of a salt crystal, would the steps be completely same, or would they be different in some places? I don’t know much about crystal growing, but I wanna know. And if so, what shape would they take? And would it need some special type of sugar to make it perfect? Could you write an article about that too?
Different chemicals have different solubilities in water. For example, you can only dissolve 30-40 g of salt in 100 mL of water before it is saturated. But you can dissolve up to 300 g of sugar in 100 mL of water! So you will have to take these differences into account when trying to grow sugar crystals. But other than that, the general procedure is the same.
Hi, just discovered your website, wonderful information and illustrative photos, love your handwriting on some of the photos! Lovely thanks for all the hard work and time put into sharing your valuable knowledge!
Thank you so much 😀
Glad you liked it. I love this hobby and I’ll definitely continue to share my findings.
I tried to do this on my own, and -to my greatest dismay- I cannot get my salt to dissolve in the water.
I am using tap water and a free-flowing salt from Kroger. Any tips?
Did you use hot water? Maybe you used too much salt, so it appears like a lot of it did not dissolve. Just keep stirring it for 10 minutes while heating – then the solution should be good to go. You can recycle the extra salt.
so far im getting okayish results! how do you avoid these little “parasite” crystales that pop up all around the bigger one all the time and want to merge with it?
Nice. That’s one of the big problems in growing crystals. It’s especially hard to control for table salt. You can try 3 methods:
a) Transfer the crystals to a smaller container. My makeup jar lids only held around 7 ml of solution. Therefore, the single crystal in the middle could “absorb” all of the excess salt as the water evaporated, and less parasitic crystals formed as a result.
b) Cover the whole setup completely to limit dust and air movement. A picture is shown in the guide.
c) Buy a cheap plastic dropper. Use the dropper to “blow away” the parasitic crystals that are threatening to stick to your nice crystals. This method works better than using tweezers, because tweezers will scratch those crystals.
Hey thanks for your quick reply! I’m already doing c) also I’m transferring the crystal to a new clean container every few days when too many parasites crystals have formed. Do you think thats a good idea?
Thank you so much for your time!
If the conditions are stable enough, you shouldn’t need to transfer the crystals more frequently than once a week. Note that the bigger your main crystals get, the less often smaller crystals form at the side.
Normally it’s not recommended to keep transferring the crystals as it interrupts their growth somewhat. Rely on the dropper method more and transfer only once every 2-3 weeks, if at all. But you don’t need to stick to my suggestions. Once you’ve grown them for a while, you’ll get a feel for these things. If it works for you, then by all means, go ahead 🙂
thank you so much! love your passion for this.
This was an interesting and well written article, thank you.
Well I just had to give it a try too, but I did not have uniodized salt. But I do have plenty of crystal water softener salt. It looks good, clean white crystals, very inexpensive. And I also have distilled water. But no way, forget it, for me doesn’t work. Peculiar thing, right off the bat in step 1 there are no small white flakes on the surface, but white crusty crystals start forming up the sides of the container above the solution. Even after a week, the solution itself stays clear even with some surplus salt in it. So then I strained out the solution thru a coffee filter and started over with this in a very shallow tray. Doesn’t work either, you get lots of crystals, but they are microscopically tiny. After these form, the salt again wants to crystallize in thin air up the sides of the tray and up over the top. The little specs of crystals in there simply don’t want to grow. Weird. Well so I am just going to get myself some uniodized salt and try this again.
So there you go, just passing this along.
Hey, thanks for sharing your experience.
It’s almost certainly iodine, or another additive inside the salt – considering how the crystals like to form crust that crawl out the sides of the container. You should have much better luck with uniodized salt.
Jeepers I am having a hard time finding non-iodized salt.
Well, the search is on.
Not sure if you located the salt, but amazon carries it.
Hope this helps.
Nice, thanks man.
Had to give it a try today just needed to find Uniodized salt.
But the first portion is on its way to grow.
*) What experience have you by doing the first saturated solution, I mean the heat of the water as you mentioned that it could be that the water was too hot. I ‘ve done it now for the 1. attempt at 80°C .
*) After transfer do I have to wait until the solution completly vaporized and then fill up again to become a bigger crystal? or just let it constant beneath the water?
Hey, that’s great.
1. Don’t worry about the temperature of the water. You just need to heat it up until most of the salt dissolves and you can see the salt flakes. Sodium chloride is stable, which means accidentally boiling it doesn’t matter.
2. Don’t wait for the solution to completely dry before adding new solution. Make sure the level of the solution is always high enough to cover the crystals, otherwise they will become white and flaky. But using my setup, it’s very rare for the solution to evaporate so quickly, so there’s a high chance you won’t need to add any solution at all.
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Thanks for sharing your experience. Does the same procedure work for sugar?
Yes. It’s actually much easier to grow good sugar crystals.
Thanks! These are great! I usually see examples with CuSO4.5H2O, but NaCl is much more accessible. I teach high school chemistry – I will definitely be sharing this with my students.
I’m really happy to hear that! In fact, my high school chemistry teacher was the one who got me to grow crystals in the first place. Your students will definitely love it!
Amazing project! I’m currently doing this right now and I have a few questions.
1. Do you stir the solution as it boils or do you put everything in and then boil it
2. How much solution did you use. I used 40g of salt and 100ml of water
1. It doesn’t matter, I did the latter.
2. I normally prepare 200g/500ml batches so that I can grow more crystals at once. You can store the extra solution in the jar. Doing so makes it more convenient for you to grow future batches, since you don’t have to prepare any more solution. But 40g/100ml is enough for a decent first attempt.
One warning that you may want to consider adding: high concentration salt water, particularly with solid salt left at the bottom, can permanently damage stainless steel cookware, as I just discovered when preparing the solution to try this myself. So if you used a metal pot to heat the solution, it needs to be transferred to a different vessel to cool and stabilize. Thanks for the instructions, looking forward to seeing the results!
I see, thanks for telling me that. I normally do mine in beakers, so I haven’t experienced it myself. But you’re right, I’ll include a warning on this in the guide. Sorry about your pot 🙁
CuSo4 is better, no using NaCl! (5H2O)
That was amazing. Congratulations! I will try to do a crystal!
Wow! I saw this on Twitter and it is incredibly cool. Thank you so much for providing such excellent instructions and photos, Chase; I know what I’m going to be doing first thing in the morning and probably for the next year! (I only wish I knew about this during quarantine!)
I’m really happy to hear that. It always feels good to get excited about something in the morning; and that’s exactly how growing crystals makes me feel. Best wishes and good luck 🙂
Should the water be Tap or distilled?
Both works. I only used tap water, but distilled might give slightly better results.
Hi, I’ve tried this out but my crystals always turn opaque even if I place a cover over them. Is there anything I can do about this?
Make sure you’re not using iodized salt.
Maybe sprinkle a few grains of salt into your saturated solution, then seal it and store the jar away for a week? That should give enough time for it to stabilize. Then, continue growing using the same method that you used.
So very interesting. Now our tap water has a fair mineral content. Would it be advisable to use bottled water? Or distilled water?
Distilled water would probably give you the best results. But sometimes impurities can make them grow in interesting ways, so it’s a good idea to try all of them too.
Do you have a possibility to check what crystal size relates to 1/2 spoon of salt, 1 spoon etc? 🙂
A big crystal contains about as much salt as a teaspoon. Quite little tbh.
Your crystals are very impressive! Thank you for the comprehensive guide, I’m going to give this a go!
Have you ever thought of making any home grown crystal with strong solid material outlook to make jewelry item.
I just thought making homemade diamond sort of pendent or ring from crystals would be an interesting project to undertake.
The crystals dissolve in water, so it’s not a good idea to make jewelry with them. Some people have suggested casting it in resin to protect it – this might work.
This is beyond amazing, I didn’t know it was possible. Thanks so much for sharing your knowledge Chase!
Hey Chase, thank you so much for this. I’m trying this out right now! But I have two questions: you say to pour quite a lot of solution(50ml) into a plate, where then just a few little seeds emerge when it evaporates. Then after choosing a proper seed, you only add very little more solution to the make up lid. Is this really enough to grow a quite bigger crystal when before you only got a few small seeds with a lot more solution? Do I have to “refill” from time to time for it to get bigger?
When the crystal gets bigger and the solution evaporates and I want it to grow even bigger, do need to add a lot more solution so it’s always fully submerged in liquid?
Thanks in advance for your help!
Ah and will the crystal also grow if you prevent evaporation completely and keep the seed in a atmospherically closed space for a long time?
Nope. This method relies on the fact that as salt particles crystallize out as water evaporates.
Yes, the 5 ml of solution I added to the makeup jar lid was enough to grow a clear crystal up to almost 1 cm in length. But you are right, when the level of the solution decreases, you have to add more saturated solution so that the crystal is completely covered. Otherwise, it surface will become dry and flaky, which isn’t very pretty.
To do this, just use the dropper and transfer several drops of the solution you prepared and stored previously in the big jar into the makeup jar lid.
Thanks for the informative reply! I already have some very small seed cubes at the bottom of my jar!
Wow that’s fast. It’s good sign, keep it up.
Very cool project! Excited to try 🙂 thanks chase!! Great post
I love seeing these perfect crystals. I imagine the atoms all lining up just perfectly in rows and columns. It also makes me think of the way rocks must form in the earth–very slowly, over great spans of time. Thinking about your salt crystals as rocks made me curious–are they harder to crack in two when they are “pure”? Are white salt crystals easier to break?
A crystal of sodium chloride is always pure, because crystallization is a purification process – although small amounts of impurities might get trapped inside. Provided the crystal is grown well (transparent, straight edges), the hardness is the same for any type of salt. But if there are defects in the crystal, like cracks or hopper growth, then it makes the crystal physically weaker, so it’s easier to break.
Does the crystal need to remain completely covered by the solution at all times?
Yes. Once the solution dries, the surface of the crystal will be covered with crust.
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This is very informative and dope
Interesting guide, can’t wait to try it! One point of confusion:
“If the crystal looks like picture 3, it means you have to select another seed crystal and try again.
If it looks like picture 4 or 5, let it grow anyway.”
The preceding graphic only contains pictures 1-4, it’s not clear which you’re referring to here
Sorry, I made a few edits and forgot to change that. It should be if the crystal looks like picture 2… and the next line: If it looks like picture 3 or 4, let it grow anyway. Thanks for notifying, I’ve fixed it.
Thanks for such a detailed process!
Very nice. Informative and beautiful. Thanks.
Saw your post on Imgur. Going to try this as a home school experiment with both iodized and non iodized. Thanks for the very clear instructions.
Awesome. Good luck, and have fun!
There are only pictures 1–4. It makes me wonder if the reference to “picture 3” in the previous paragraph is an error, too. Reasoning about it, it seems that #3 should be fine and #4 is the one that is irrecoverable.
“If it looks like picture 3 or 4, let it grow anyway.” Sorry for the mistake.
In the case of picture 4, most of the time, the crystal will not dissolve completely, so eventually it will start regrowing and form an interesting “hologram” inside the crystal.
Love this carefully documented process!
Thank you so much for this incredibly well explained guide! The photos are amazing! (btw, when you talk about accidents, you mention examples 3, 4 and 5, but there’s only 4 in the pictures)
You’re welcome 🙂
Oops. It should be examples 2, 3 and 4. I forgot to change it while making some edits. Thanks for telling me, I’ve fixed it.
Fantastic! I will try this soon. Do you have any experience growing bismuth crystals?
No, not at the moment. It’s in my bucket list.
Looks beautiful, thanks for sharing 🙂
That’s crazy awesome!
Awesome guide! I cannot want to try this myself. I hope you and your family are all doing well and thank you for sharing!
Thank you! I’m really glad you decided to try it out. Good luck, and have a good time.
This is great! Thanks so much for the detailed lesson. I am a high school science teacher and after seeing your post on Reddit and checking out your website, my class will be attempting to grow some crystals!
That’s great. It is indeed a good educational activity. Have fun!
sick crystals! Wow I never thought salt could be so cool. Very inspring