Igneous Rock Textures Quiz

What is the composition of a glassy texture in igneous rocks?

• Composed of two distinctly different crystal sizes.

• Composed of unordered atoms and resembles dark manufactured glass.

• Composed of mineral grains that are large enough to be identified without a microscope.

• Composed of crystals that are too small for the individual minerals to be identified without a microscope.

Which texture is produced by the consolidation of fragments that may include ash?

• Glassy texture

• Vesicular texture

• Pyroclastic texture

• Aphanitic texture

Which texture is associated with a frothy volcanic glass?

• Glassy texture

• Vesicular texture

• Porphyritic texture

• Pyroclastic texture

Which rock is typically light in color and high in silica content?

• Basalt

• Gabbro

• Granite

• Shale

What is the main component of felsic rocks?

• Iron

• Magnesium

• Silica

• Calcium

What causes a vesicular texture in rocks like Pumice?

• Rapid cooling without gas bubbles

• Trapped gas bubbles during rapid cooling

• Slow cooling with gas bubbles

• No gas bubbles during cooling

Which rock is not mentioned as having a vesicular texture?

• Pumice

• Obsidian

• Basalt

• Granite

Which rock is described as fine-grained and dark-colored?

• Obsidian

• Pumice

• Basalt

• Granite

What is the main difference in cooling between intrusive and extrusive igneous rocks?

• Intrusive rocks cool quickly, extrusive rocks cool slowly.

• Intrusive rocks cool slowly, extrusive rocks cool quickly.

• Both cool at the same rate.

• Intrusive rocks do not cool, extrusive rocks cool quickly.

Where do intrusive igneous rocks form?

• Above the earth's surface

• Below the earth's surface

• In the ocean

• In the atmosphere