Igneous Quiz

In which group do the rocks usually have the mineral quartz as part of their composition?

• granite, rhyolite, sandstone, hornfels

• conglomerate, gabbro, rock salt, schist

• shale, scoria, gneiss, metacconglomerate

• breccia, fossil limestone, bituminous coal, siltstone

Which relative concentration of elements is found in a mafic rock?

• a high concentration of silicon and a low concentration of iron

• a high concentration of iron and a low concentration of aluminum

• a high concentration of aluminum and a low concentration of iron

• a high concentration of aluminum and a low concentration of magnesium

Which statement best describes the formation of an intrusive igneous rock?

• Magma solidifies slowly, resulting in a coarse-grained texture.

• Magma solidifies slowly, resulting in a fine-grained texture.

• Magma solidifies rapidly, resulting in a glassy texture.

• Magma solidifies rapidly, resulting in a clastic texture.

Which characteristic provides the best evidence that obsidian rock formed in an extrusive environment?

• layers of rounded fragments

• noncrystalline glassy texture

• quartz

• mineral cement between grains

For an igneous rock to be classified as rhyolite, it must be light colored, be fine grained, and contain

• calcite

• white quartz

• distorted bands of large mineral crystals

• mineral cement between grains

Compared to felsic igneous rocks, mafic igneous rocks contain greater amounts of

• pyroxene

• pink feldspar

• olivine

• iron

Which igneous rock has a vesicular texture and a felsic composition?

• Rhyolite

• Granite

• Pumice

• Scoria

Which processes lead directly to the formation of igneous rock?

• glassy

• vesicular

• compaction and cementation

• melting and solidification

Which texture best describes an igneous rock that formed deep underground?

• fine grained

• coarse grained

• fine grained

• coarse grained