The Fizz Test for Limestone & Marble Rocks

Many rocks can look alike. Sometimes telling the difference between a limestone or marble and other rocks such as shale and quartzite can be difficult. One way geologists test the rocks is by performing the acid or “Fizz” test. Calcite is the main component of limestone rocks and its varieties like oolitic limestone, fossiliferous limestone, coquina and marble. The calcite mineral is made of calcium carbonate which reacts with acid. Other varieties of calcium carbonate minerals such as aragonite and dolomite will also fizz during this test.

Ask-a-Geologist #4: Why do geologists tests rocks for calcite?

Today we have another great geology question from one of our readers.

Terrance writes: Why do scientists check rocks to see if they contain calcite?