Real Minerals and Rocks - Section B: Igneous Rocks

1. What is the difference between aphanitic and phaneritic?

Select one:

a. In aphanitic rocks the crystals are large enough to be identified with the naked eye, while in phaneritic rocks they are not.

b. Phaneritic rocks cooled slowly and therefore have small crystals, while aphanitic rocks have large crystals and cooled quickly.

c. In phaneritic rocks the crystals are large enough to be identified with the naked eye, while in aphanitic rocks they are not.

d. Aphanitic rocks have small crystals because they cooled slowly, while phaneritic rocks have large crystals and cooled quickly.

2. Basalt is the most common volcanic rock on Earth. These rocks may show great diversity in texture, fabric, and to a lesser extent, mineralogy.  

Name two minerals you can identify in your specimen:

3. Name two tectonic settings where basalts form:

4. Name two minerals you can observe in the peridotite specimen: