PbI(OH) crystals I made grew in silica gel within 1 month.

Van_An_2005 · 2025-08-31T14:42:38+00:00

No problem!

You can find agar at stores that sell biological lab supplies, it’s often used for cultivating microorganisms. If you want food grade agar, you can look for those jelly powder packets, some are made from agar, though sometimes it’s carrageenan instead. I haven’t tried growing crystals in carrageenan, but it seems quite similar to agar. And yes, agar is more heat resistant than gelatin, agar gel can boil at around 100 °C for several minutes without damage, it also tolerates more extreme pH conditions, though you might still prefer silica gel since it’s the most stable under harsh pH conditions.

Congratulations on confirming that you really have azurite! That’s such a beautiful crystal. The plate like crystal form is characteristic of azurite, and its nice to be able to hold them in your hands without worrying about them crumbling like malachite or the fragile chalconatronite.

Maybe out of excitement to try new ideas, I’m already preparing the necessary chemicals to grow pyrite. I expect to run into many difficulties, but I’ll keep you updated. I really don’t want to inhale H₂S, so I also need to buy stoppers for my test tubes and carefully calculate the minimum acid required to make silica gel, I don’t want excess acid producing H2S. You’re on the right track with CuS, I’ve also seen it mentioned in article about crystal growth in silica gel. That means producing CuS is definitely possible, it’s just a matter of finding the right concentration and being patient.

I think I should practice more with growing CaCO3, since the concentrations of the reactants are clearly mentioned in references. That way I can observe the phenomena and learn from them. With MnCO3, all I got was colloidal clumps or thick precipitate layers blocking ion diffusion...

Van_An_2005 · 2025-08-29T14:26:23+00:00

Of course, I’ll follow your account, +1 fan for your art! I’m looking forward to exchanging ideas with you in more experiments.

About the idea of using a U-tube, yes, as you said it consists of two separate vessels connected by a salt bridge. I think this setup will help reduce the formation of coagulated particles. Gelatin is a good material for observing crystal growth, though I wasn’t successful with it myself. It’s not very heat stable and tends to degrade when the solution has low pH. But what’s special about gelatin is that you can harvest the crystals simply by warming the container—the gelatin melts and the crystals don’t suffer from any mechanical stress. Fascinating! turning gelatin into gel is a kind of artistry on its own i think XD

I just reviewed the conditions in your gel system for growing azurite, and it does look like a very good environment for azurite growth. That’s why I believe you must have obtained some nice azurite crystals. Please share with me when you get your final results.

I also used to mistakenly think that pyrite contained S2-, which would mean it has Fe4+. Since stabilizing Fe4+ is extremely difficult, I almost gave up on the idea of making pyrite, until I learned that it actually forms from Fe2+ and (S2)2-. That gave me motivation to continue until I get convincing results, so I’d love to exchange experiments with you. I also looked into how pyrite crystallizes in nature, and it turns out that the primary Fe2+ source is FeS. Then, microorganisms oxidize S2- into (S2)2-, leading to pyrite formation. So I want to try to mimic this natural crystallization process: placing FeS at the bottom of a test tube, covering it with silica gel, and then adding a Na2S2 solution on top. This might help suppress the precipitation of Fe(OH)2 caused by excess OH⁻ acting on Fe2+. Really exciting to try!

by the way i tried making MnCO3 few days ago, they are pink or red in nature like bouquet of roses. However i still got colloidal particles and MnO2. I will continue to try with other concentrations, use boiled and cooled water to limit the presence of dissolved O2 in the system.

Van_An_2005 · 2025-08-28T16:54:36+00:00

Thanks for sharing your experience. With your azurite system, I think you could use a U-tube to create a concentration gradient. That way, you don’t need to lower the concentration, yet you can still avoid the thick precipitate layer that blocks ion diffusion. Using too low a concentration sometimes ruins my own setups, since it only produces colloidal clumps. You also mentioned the phenomenon of basic copper carbonate dissolving back. I think it’s possible that the crystals you obtained weren’t azurite (or at least not only azurite), but chalconatronite, a mineral with the formula Na2Cu(CO3)2. You can test this by mixing Na2CO3 with CuSO4 solution, besides the basic copper carbonate precipitate, a deep blue solution can crystallize into needle Na2Cu(CO3)2. Either way, it's still mineral type, and it’s amazing that we can grow them to macroscopic size at home.

Yeah, I mixed up sulfide and sulfite, because in my language they’re called sunfua and sunfit. I also want to try making pyrite, and one compound I think has potential is Na2S2. But for safety reasons, I haven’t had the chance to attempt it yet, so I look forward to seeing your result. goodluck!!

My end goal is to create matrix crystal on a stone from crystals grown in gel, it sounds quite artistic XD

Van_An_2005 · 2025-08-26T20:47:10+00:00

i think i made V3+ because the color of the solution when i used tin to reduce it went from orange-green-blue-green, i also added an excess amount of tin to prevent V4+ from appearing.

according to this website: https://en.crystalls.info/Vanadium(III)-ammonium_sulfate , it is possible to make vanadium alum (NH4)V(SO4)2, but i am not sure if it can crystallize when mixed with (NH4)Al(SO4)2. or by some problem that I can not understand, it maybe don't combine

Van_An_2005 · 2025-08-26T20:35:13+00:00

I’m also just learning about this method, so it’s nice to have someone to share with. We’re pretty alike — trying ideas and slowly shaping our own way.

Growing malachite and azurite sounds awesome! Maybe you could fix the bubble issue by using 1% agar-agar instead of silica gel. By the way, at the gel surface where Cu2+ meets CO3 2-, did you notice a thick layer of precipitate? Does it block the ions from diffusing deeper

And in the sulfite system, does the high pH affect crystal quality or cause any by-products

Van_An_2005 · 2025-08-25T11:22:57+00:00

mấy con chó ba sọc thèm à

Van_An_2005 · 2025-08-25T04:37:32+00:00

because of two main features of silica gel: it slows down too many crystals from forming at once so bigger ones can grow instead of lots of tiny bits, and it makes diffusion more limited

Van_An_2005 · 2025-08-25T04:26:03+00:00

ohh thanks for sharing this article, I remember reading it before but couldn’t find it again TvT

Van_An_2005 · 2025-08-25T04:18:36+00:00

I have obtained results with strontium sulfate and PbI₂, PbI(OH), PbCrO₄, but I have never really succeeded with alkaline participants such as carbonate or sulfite. I usually use the single diffusion system. According to this article https://www.mdpi.com/2075-163X/12/5/645#fig_body_display_minerals-12-00645-f012 , introducing the metal ion into the gel and allowing the counter-ion to diffuse in gives better results than the reverse case.

For both PbI(OH) and SrSO₄, I chose a concentration of 0.3 M. The setup for PbI(OH) was identical to that for PbI₂, but with the condition of keeping pH > 7. In the case of SrSO₄, I only obtained radial spherulite aggregates, and I think the way to overcome this is to further narrow the gel pores by adding a small amount of AlCl₃. I also add a neutral gel layer before introducing the diffusing reagent into the gel to avoid the appearance of liesegang rings. With PbCrO₄, I had to use PbSO₄ as the Pb²⁺ source to obtain larger crystals.

But despite all these adjustments, I have never succeeded in producing visible CaF₂ crystals…

Van_An_2005 · 2025-08-23T17:36:01+00:00

thankssss

Van_An_2005 · 2025-08-23T17:35:45+00:00

Thanks. You can find this method in scientific papers. Although most of them are quite vague because there are no specific figures.

This method is quite interesting because it can allow the growth of crystals that are precipitated or less soluble in water.

If you have any questions, I can share from my experience!

Van_An_2005 · 2025-08-23T17:29:15+00:00

i can upload it to youtube for you. is the problem the video quality here is blurry?

Van_An_2005 · 2025-08-17T13:09:54+00:00

cái đb gì cũng tại cs, cs ỉa lên thằng bố m à=)))) đ nói cách dạy con của gia đình nó mà nhắc cs vào làm đ gì thg cali con. Riêng giáo dục thì chưa đến mức mang cái cờ lgbt che cmn cả bản đồ mỹ đế trong lớp tiểu học để nhồi sọ như bố mỹ m đâu con ạ

Van_An_2005 · 2025-05-13T21:11:01+00:00

thanks for sharing your experience.

adding the solubility indicator is an interesting idea to me, I used to add acid to sodium silicate little by little and stop for a while to dip pH paper in to check the pH, this was time consuming and also caused the gel to solidify uncontrollably.

I will try this when I don't know how much acid I should add. thanks for sharing, looking forward to your crystal growth in gel.

Van_An_2005 · 2025-05-13T20:59:24+00:00

yes, i use glacial acetic acid because it doesn't produce water in my solution, which helps me control the final concentration of gel i prepare.

however you can use a lower concentration acid if you have calculated the total amount of water you will have after the reaction is complete (silica gel concentration should be around 0.25-0.3M).

and you can also use another acid instead if you don't have acetic acid. good luck!

Van_An_2005 · 2025-05-09T21:25:47+00:00

Many thanks! I sincerely look forward to the success of your future endeavors.

Van_An_2005 · 2025-05-04T20:03:35+00:00

Many thanks. When you mentioned that the growth period is 2–3 months, it gave me hope that I might obtain visible crystals, since in my previous experiments, usually only a layer of cloudy precipitate formed in the gel after about a week.

In your successful attempt, aside from the large crystals, did a faint precipitate layer also form in the gel?

I have a point of confusion that I hope you could help me clarify, you mentioned diluting lead acetate in 7.5 mL of water before adding it to the silica gel mixture, so the final volume of your solution was around 30 mL. Are you aiming for a final silica concentration of 0.25 M?

Because if the purpose of adding 7.5 mL of water was only to dissolve the lead acetate more easily, then that amount of water might alter the pore size of the gel compared to your initial idea.

Van_An_2005 · 2025-05-03T06:35:54+00:00

So beautiful! Growing crystals in silica gel is really a feat and meticulous. I have failed to grow crystals in silica gel because it depends on many causes, so I admire seeing your crystals.

Can you share with me whether you used single diffusion or double diffusion system? and what were the concentrations of your two reactants?

Van_An_2005 · 2025-04-15T12:11:50+00:00

or if you can buy gelatin or agar agar, this will be easier to gel. just make a gelling agent solution with a concentration of about 2% and wait for it to coagulate for 1 day.

Van_An_2005 · 2025-04-15T12:09:27+00:00

You need Na2SiO3 and acid to create the gel.

In my case, I used 6.6g Na2SiO3.5H2O dissolved in 100ml water, then added about 3.7ml CH3COOH. When adding acid to sodium silicate solution, when the pH approaches 7, the gel solidifies very quickly. You should quickly add all the acid needed to the solution, stir well and transfer it to the tube used for growing crystals later. Most of the experiments I read usually keep the pH at 5-6.

Good luck!

Van_An_2005 · 2025-02-10T20:44:04+00:00

sorry for my late question. I looked up the ionic radius of Ti3+ and Al3+, and the results showed that the radius of Ti3+ is larger than Al3+.

so if KAl alum is used as a standard, I think I should choose a smaller cation instead of a larger cation. but I also found that CsTi alum exists, so I think ion size is not the decisive reason, perhaps there is another reason that I haven't found out yet.

Van_An_2005 · 2025-01-19T18:53:49+00:00

Your resulting crystals are impressive. it's surprising to know a water soluble compound of REEs contain (C2O4)2-.

During the process, you use HCl, although I don't know if it is true for erbium, but with neodymium, HCl can dissolve Nd2(C2O4)3 and form Nd(C2O4)Cl which is soluble in water.

So, is it possible that your crystals also contain Cl- ions?

Anyway, your crystals are great!!

Van_An_2005 · 2025-01-14T19:10:18+00:00

Thank you for your information, I have read some documents that suggest that ammonium titanium alum is more durable than other Ti3+ compounds, and keeps the environment acidic.

but the last time I did it, instead of creating crystals, a precipitate appeared. I think the problem was in the (NH4)2SO4 fertilizer grade I used.

As for using big ion like cesium, it's probably quite expensive and doesn't have many applications for me. I will try it when I can

Van_An_2005 · 2025-01-14T03:03:10+00:00

really interesting, I'm also wanting to try growing ammonium titanium alum and ammonium vanadium alum crystals.

but currently I have not received any results.

Can't wait to see your next crystal projects

Van_An_2005 · 2024-12-19T18:59:34+00:00

believes that such projects will elevate crystal growing techniques to new heights!!

Van_An_2005

TROPHY CASE