Are my seashells real?

[Giroliro3]

I got them from dollar general and they smelled like the ocean when I bought them, they also had these particles on thrm like sand or dirt. Whenever I take them out of my tank they dry up and they start getting white-ish tints to them. Whenever I put them back in my tank they turn their regular colors again.

I also got some rocks from the same company at the same store.

I haven't noticed any ph changes with my tank either

 

[Delapool]

Hi, tried putting any vinegar on them to see if you get any bubbles?

 

[Giroliro3]

I was going to do that, but I can't find any evidence on the internet that they bubble like rocks. The only thing I've heard was that they dissolve.

 

[Delapool]

The sea shells will still bubble as well (if from the sea) as also composed of calcium carbonates (same as limestone rocks).