I needed some limestone to work some cement experiments trying to replicate both the Portland cement patent, and to make slaked lime for mortar mix.
This meant I had to be able to go about identifying Limestone. Luckily since limestone is calcium carbonate, (a base). Simple chemistry ensures that when it makes contact with acid it will fizz (which is CO2 being released) as the acid and the base attempt to counteract each other.
If you have a large weathered rock, you may get better results if you smash it into little pieces – limestone is brittle and crushes well. Then simply drop some strong vinegar or weak muriatic (hydrochloric) acid on the rock. If it fizzles, then it is a good bet its limestone.
This is a pretty easy thing to do. I have done it successfully several times. Limestone is a vital construction material as it is a key ingredient of cement.
At some point I want to try my hand at making my own cement from limestone, but for now the farthest I have done it to make my own slaked lime in the foundry I made some years back.
I hope that as I dig into the hillside at my land I will find more limestone. Especially since I have a lot of moving water. A cave would make my day.