Vinegar may be a common household staple, but did you know that it can actually dissolve rocks? That’s right! The acid found in vinegar is capable of gradually eating away at certain types of minerals, breaking them down into smaller and smaller pieces, leaving behind crystals that are potentially hidden inside what might otherwise be an assuming rock.
In this video, it’s easy to see that there are large amounts of calcite exposed which can easily be removed by soaking them in vinegar. But if you look closely at these rocks, you’ll also see small amounts of pyrite crystals exposed. Could there be more inside? The hope is that there are many more pyrite crystals hidden in the rock. Allowing these rocks to soak in vinegar will remove the calcite eventually giving us a look at what’s inside!
If you think you’d like to give dissolving rocks in vinegar a try yourself, its actually very easy to do. I put together a step-by-step guide on how to do it not to long ago. You can read the article right here: Dissolving Rocks To Expose Crystals (How To Guide).
How Long Does It Take?
But only time will tell whether or not there’s more crystals to be found inside these rocks. To do this type of thing properly, it requires patience. In this case, the rocks were dissolved in table vinegar for about 2 weeks. The other thing to keep in mind is that the vinegar loses its potency fairly quickly. So if you decide to try this yourself, you should plan on changing out the vinegar every couple of days.
So what were the results? Check out the video and see for yourself!
Check Out What’s Inside!
How To Expose Hidden Crystals With Vinegar (and other acid types)
Below is a condensed instructional guide on how to dissolve your own rocks in vinegar in order to expose crystals that might be hidden. However, I strongly suggest that you read the complete guide here: Dissolving Rocks To Expose Crystals (How To Guide).
1. Prepare Your Acid Solution
Vinegar once again makes things simple in this case: just dump it in the bucket until it covers the rocks. I’ve never seen any need to dilute vinegar for any but the most sensitive tasks, and when we’re dissolving matrix off of crystals we want it as strong as possible.
The first step when we’re working with chemicals is always to don our PPE. I can tell you, from experience, that even vinegar can get surprisingly nasty if enough of it gets in the air. Any other acid can do serious damage before you realize what’s going on.
In the case of any other acid, we have a simple protocol that must always be followed.
Acid goes into the water, never vice versa. When you pour water over an acid it creates a thermogenic reaction as it dissolves, increasing the heat of the solution. In small amounts, this can cause a bit of bubbling.
In larger amounts, this will cause a series of unfortunate events. The water will boil, flinging droplets of low pH acids, and can cause a burst of steam. Steam can scald you, and this steam will be carrying acid along with it to make your day just a bit worse.
Never, ever pour water into or over an acid. Write it down if you have to, this is one of the axiomatic rules of chemical safety.
Muriatic acid is the strongest thing I would use without dilution.
Fill the bucket just to a level over the stones to be cleaned.
2. Soak Stones in Acid
Next up you’ll want to carefully place your stones in the bucket if you haven’t done so already. Vinegar and other weak acids can take a few weeks to show serious results. Stronger acids will often take a few days to a week.
Be careful about allowing stones to sit too long in strong acids. Some can be etched or damaged by a very long exposure, although the majority will be fine.
In any case, either seal the bucket or put something over the top that’s resistant to acid. Plywood is a decent bet with the acids listed above. The important thing is to have it closed and placed somewhere that it won’t be knocked over.
When you check the stones put on your respirator. Often you’ll have fumes built up inside the sealed bucket which release when it’s opened. This can be uncomfortable, especially if you’re working with muriatic acid.
Check on the stones periodically. If you’re not sure if they’re done you can remove a specimen, dip it in baking soda saturated water, and then take a look. Often a wire brush will take off the rest of the host without any issues after a few days.
Keep it going until you’re happy with what you see.
3. Neutralize Acid
Create a bucket with baking soda water. I usually saturate mine but it’s not necessarily required, we just want to force the acid to react. Remember to add the baking soda water to the acid and not the other way around.
Do this slowly. Often the reaction can be mildly exothermic and you don’t want things to heat up too much.
When acidic and basic substances react, the result is a movement towards a neutral pH of 7.
You want to reach at least a 5 pH before you go any further. This is usually easy enough: the solution will quit reacting when you add more baking soda when the acid is neutralized. You can also use pH test strips to handle this.
Depending on the acid, the next step may be more or less difficult.
4. Dispose of Waste Responsibly
The acids I listed at the beginning of this article are all safe to dispose of without requiring you to head to the local dump’s HAZMAT area.
There are some pretty handy guidelines to follow.
It basically boils down to what ended up in the acid. Remember the beginning where I insisted that you know what your stones are? That’s now important.
If all you removed was a calcium carbonate compound like calcite or aragonite then you can dump the neutralized acid down the toilet or tub. If you opt for the latter then run cold water with it to prevent any unintended exothermic reactions.
On the other hand, if you have metallic oxides or other salts in the mix you’ll have to visit the local HAZMAT facility. Most places will take it with a minor charge.
Once the acid is disposed of, you’ll be able to manually remove any remaining muck on the stones and enjoy your shiny, newly liberated crystals!