Index Minerals

Index minerals are specific types of minerals used by geologists to identify and classify rocks, especially metamorphic rocks. They form under particular temperature and pressure conditions, so their presence indicates certain metamorphic grades or environments. By examining which index minerals are in a rock, scientists can determine how much a rock has changed from its original state, helping to understand its history and formation conditions. Examples include garnet, kyanite, and staurolite, each associated with specific temperature ranges during metamorphism.