help to name a rock.

Question

Answer 1

Hard to tell from the picture, but looks like it may be tufa. Does it bubble up with small bubbles if you place acid on it?

Answer 2

Yes,sir  it bubble up on acid.

Answer 3

Ok so then it is indeed tufa. Tufa is a form of calcium carbonate (i.e. calcite or aragonite) that forms from water precipitation such as hot springs that forms under conditions that cause it to bubble with air pockets. It can be used as an ornamental stone when in layers.

Answer 4

Thank you.