The two rocks primarily composed of a mineral that bubbles with acid are limestone and dolomite.

Here's why:

* Limestone is primarily composed of calcite, a mineral that reacts with acids (like hydrochloric acid) to produce carbon dioxide gas, which causes the bubbling effect.

* Dolomite is composed of dolomite, a mineral that also reacts with acid, albeit more slowly than calcite. It also releases carbon dioxide gas when reacted with acid, causing bubbling.

This reaction is a key characteristic used to identify these rocks in the field.