Chapter 2.4, Problem 1A

Place each of the igneous rocks supplied by your instructor on a numbered piece of paper. Then complete the igneous rock chart in Figure 2.12 and identify each specimen. To identify an igneous rock, follow these steps.

Step 1: Identify the texture of the rock.

Step 2: Determine the minerai composition of the rock by

a. Identifying the abundance of major minerals

or

b Estimating the mineral composition USing the color index

Step 3: Use the Igneous rock identification key In Figure 2.10 to identify the rock.