if its a carbonate rock, you should see it begin to develop bubbls on the rock surface almot immediately.
First check the hardness. Find a reference to MOH's hardness scale nd then, using a piece of glass , try to scratch it with your samples. Then find som pieces of material that is progressively softer (if you cant find a feldspr, you can use a acrylic plastic for a hrdness of 3-4)
Then , get a mineral book (Pwterson field guides are good for your first reference) and compare the hardness with the white rocks you have.
Also, see the "Cleavage" (this is how the mineral breaks, with strait lines or flat surfaces or random concave breaks (conhoidal fractures).
All these are indicative of the mineral type.
A white rock, usually i a feldspar, quartz, or gypsum, or calcite.
The very clear ones are probably some kind of quartz (Id try to find where the source is because there may be deposits of crystals.