Taylor

Being able to tell the difference between a marble and an igneous rock like granite can be challenging. Lucky for us, we have examples of each sitting side-by-side at Stop 18. The marker on the left is made of pink marble, while the marker on the right is made of pink granite. They are both made of crystals of about the same size. The key difference is that the granite is made of several different types of minerals, whereas the marble is only made of calcite. The dark streaks are caused by impurities in the rock. Many marbles have these dark streaks running through them.