The (geologically) recent volcanic activity in Yellowstone National Park is ________.

Nonmetallic minerals resources are commonly divided into two categories: building materials and ________.

Which of the following is made of microcrystalline quartz?

A coarse rock composed of poorly cemented shells and shell fragments is called ________.

Calcite is the main mineral constituent of the sedimentary rock limestone and of the metamorphic rock marble.

Erosional retreat of a(n) ________ leads to enlargement and extension of a wave-cut platform in the inland direction.

The 1943 eruption of Paricutin in Mexico was characterized by ________.

Which of the following best describes seamounts and islands of the deep ocean basins?

In sedimentary rocks, lithification includes ________.

Hornblende and the other amphiboles have what type of silicate structure?