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GeneralI made natrolite on accident?!?!?!

12th Jun 2018 21:27 UTCNathan Jaskela

I’ve been cleaning my quartz with hydrochloric acid and after cleaning I neutralize in a plastic cup with bling soda and water. I use cheap aluminum (mixed metal) tongs to transfer with... well anyways, the cup of baking soda water sat with the tongs in it (and whatever other debris that had still been on the quartz) for a couple weeks and when I removed the tongs and poured the water out there were tons of crystal formations at the bottom of the cup that are still there! When tapped with metal very gentle they make a ting sound like glass but are very fragile. Im thinking I made natrolite seeing as the chemical composition is Na2Al2Si3O10 · 2H2O , which each piece or tool I use in the process has those elements in it. Could it be possible I made Natrolite/zeolite (something in that family) because the acid broke down the molecules and neutralizing it all brought them back together to form that?!?! Here’s a picture, tell me what you think!

Thanks, Nathan

12th Jun 2018 21:43 UTCJolyon Ralph Founder

Break one off and put in water, does it dissolve?

12th Jun 2018 23:58 UTCNathan Jaskela

-- moved topic --

13th Jun 2018 20:27 UTCGeorg Graf

Hi Nbj1987,

which mineral/substance you cleaned away from Quartz? Calcite?

Kind regards, Georg

23rd Aug 2019 01:18 UTCNathan Jaskela

It was calcite :) sorry for the SUPER late reply.

13th Jun 2018 21:02 UTCcascaillou

HCl doesn't dissolve quartz. So you could end up with either a chloride or a carbonate of Na, and/or Al if the tongs where partly dissolved, and/or Ca if there was some calcite present. So the question is: was calcite present along with the quartz? were the tongs corroded/attacked by the acid?

But considering you didn't mention any of that, I'm assuming we're left with only Na, Cl and CO3 (and probably OH too considering one usually use an excess of soda for neutralizing an acid).

So, considering sodium chloride doesn't crystallize in needles, I'd rather consider a carbonate of sodium (either as carbonate or more likely hydrogenocarbonate). Although sodium chloride should also be present, aside from the needles.

23rd Aug 2019 01:08 UTCNathan Jaskela

Hello, sorry for the late reply! I was dissolving calcite and yes, the HCL was attacking the tongs. (Not to the point of them dissolving but it definitely tarnished/very slightly pitted them.

13th Jun 2018 22:30 UTCGary Weinstein

How pure was the HCl? If you used pool cleaner (muriatic) then it is impure HCl and contains some HSO4. The most common needle crystal formed by our cleanings would be Gypsum (Selenite). This is why Joylon asked if it dissolves. Or a salt, though those aren't needles.

14th Jun 2018 10:58 UTCFlorian Baur

To make such amounts of Natrolite you need a lot of Al3+ and Si4+ in solution. HCl or NaHCO3 won't dissolve your aluminium tongs as aluminium metal has a very thin layer of Al2O3 on the surface that protects the metal. And SiO2 (quartz) is very stable against HCl. To synthesize silicate crystals you usually need an autoclave, an apparatus where you have water at high temperature (300 °C and higher) and very high pressure. Under these conditions you can dissolve SiO2 but not in HCl.

So it's more or less impossible that you got Natrolite.

A sulfate as Gary Weinsten suggested seems probable, another possibility is a hydroxide, Ca(OH)2 for example though I'm not sure it forms such nice crystals. The crystals suggest that it's a material that is somewhat soluble in water so it slowly precipitated. If it's insoluble it comes out all at once and forms a powder of microcrystals.

If you want to, you can mail me some crystals (to Germany) I can do XRD and EDX measurements. Then we'd know for sure.

14th Jun 2018 11:34 UTCReiner Mielke Expert

HCl will dissolve Al. If you don't believe it then try it.

14th Jun 2018 15:13 UTCFlorian Baur

You're right, I was under the impression it would react so slowly that nothing would happen. Still, Si4+ will certainly not go into solution. So it'd be interesting to know what those crystals are.

14th Jun 2018 17:20 UTCJeff Weissman Expert

Florian is correct about zeolite synthesis - fairly easy to make, even at lower temperature of about 110-150 °C, but high pressures and some amount of Na-Ca-Si-Al in solution is required, plus usually some type of template or clay. Zeolites will not form at the conditions here - close to room temperature and atmospheric pressure, even if the chemistry was correct, which it isn't in this case.

14th Jun 2018 17:50 UTCThomas Lühr Expert

I can see only one kind of crystals. IMHO, they all are still the initial substance, "baking soda" or what ever was used.
IF there would have happened any reaction then we should see at least two differtent substances: at least one reaction product and remaining baking soda. It is highly unlikely that all of the baking soda reacted - in this case we should see only NaCl cubes

15th Jun 2018 02:22 UTCDoug Daniels

Reiner - yes, HCl will dissolve aluminum. But, the OP said the Al tongs sat in a baking soda solution. A bit different on the pH side of things. Not likely that the Al would dissolve in that solution, and you also would not dissolve enough silica to form that amount of natrolite.

15th Jun 2018 02:33 UTCAlfredo Petrov Manager

Al will dissolve slowly in baking soda solution at ambient temperature and pressure, but the mineral formed is dawsonite (as per PXRD carried out by John Attard).

15th Jun 2018 06:00 UTCDoug Daniels

But, in a large amount? If so, the tongs would be essentially gone.

15th Jun 2018 06:32 UTCAlfredo Petrov Manager

Right, Doug, I doubt it too. But we haven't seen a picture of the tongs, so it's hard to say how much they might have been etched. He did say they were soaking in the baking soda water for a couple weeks.

23rd Aug 2019 01:15 UTCNathan Jaskela

The tongs were not dissolved, only the outer “stainless” coating had dissolved in prior uses. I no longer have the tongs but there was VERY slight pitting/discoloration, nothing major.

23rd Aug 2019 03:09 UTCMichael Hatskel

Hi Nathan,

Most likely a carbonate -- check it fizzes in acids.

From the description of the specimen (Quartz being cleaned of Calcite), process (HCl neutralized by baking soda NaHCO3) and the presence of aluminum tongs etched by soda (not by HCl, because it was gone very quickly), the main components in the solution were Na+, Ca2+, Al3+, [CO3]2-, [Cl]-.

-- Sulfate impurity in HCl is not enough to produce so much Gypsum.

-- Na-Ca carbonates are not acicular.

-- Dawsonite (Na-Al carbonate) is the most likely candidate - agree with Alfredo: it fits chemistry and crystal habit. Again, check it with acid.

Aluminum etched by soda will turn dark gray: alloying iron liberated from dissolved aluminum surface. It's a very fine powder and easily marks fingers. Did you observe that? (Same happens if you put aluminum-alloy items (utensils, skillet) in the dishwasher.)

23rd Aug 2019 05:40 UTCKevin Conroy Manager

Nathan, what tests have you performed on the crystals, and what were the results?

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