Here's why:
* Dolomite is a carbonate mineral similar in composition to calcite, the main component of limestone.
* Dolomite often forms through a process called dolomitization, where magnesium-rich fluids interact with existing limestone, replacing some of the calcium with magnesium.
* This process can occur deep underground in porous limestone formations.
* Dolomite is harder than limestone, with a Mohs hardness of 3.5-4 compared to limestone's 3.
While other hard rocks can be found in limestone, like flint or chert, dolomite is a common and distinctly hard rock that often forms within limestone itself.
