Tried to clean a calcite sample with vinegar and it fizzed like crazy

Found a nice piece of calcite near a creek in Austin. Thought a quick soak in white vinegar would clean it up. The thing started bubbling and fizzing like a science fair volcano for a solid minute. Learned the hard way that acid eats calcite. Anyone know a safe way to clean that stuff without dissolving it?

4 comments

4 Comments

leob582mo ago

Oh yeah, vinegar is basically a weak acid, so it'll definitely react with calcite (which is calcium carbonate, same as limestone). For cleaning, plain water and a soft brush is your best bet, maybe with a tiny drop of dish soap if it's really grimy. The fizzy reaction is actually pretty cool to see, but not great for preserving the specimen. At least you got a free science demo out of it.

the_oliver2mo ago

Notice how many household cleaning "hacks" are just basic chemistry experiments. People use vinegar on everything from rocks to coffee makers without realizing they're causing a reaction. It's wild how much damage we do trying to fix things.

kai_burns732mo ago

True, but sometimes that reaction is exactly what you want... like cleaning hard water stains off glass.

nancy_wood15d ago

The fizzy reaction with vinegar and calcium carbonate is actually a chemical reaction, not just a cool demo. Vinegar (acetic acid) breaks down calcium carbonate into calcium acetate, water, and carbon dioxide. That fizzing is the CO2 escaping, which is why it looks so dramatic. But here's the thing, it's actually etching the surface of whatever you're cleaning, especially if it's a porous stone like limestone or marble. Over time, that gentle acid will leave a dull, rough finish instead of a clean one. A little dish soap and water is way gentler and won't damage the specimen's natural look.