Expert-Level Rocks and Minerals Quiz

You find an unknown mineral. It scratches fluorite but is scratched by orthoclase. It does not react to hydrochloric acid and has a non-metallic luster. Based on this information, what is the mineral?

• Quartz

• Apatite

• Calcite

• Gypsum

A rock sample contains garnet, kyanite, and staurolite. What can you logically deduce about the formation conditions of this rock?

• It formed at low temperature and high pressure.

• It formed at high temperature and high pressure.

• It formed from volcanic activity.

• It formed in a low-pressure, surface environment.

Two igneous rocks are found: one has a porphyritic texture and the other is vesicular. What does this difference indicate about their cooling histories?

• Both cooled quickly, but one contained trapped gas.

• The porphyritic rock cooled in two stages, while the vesicular rock cooled rapidly at the surface.

• The vesicular rock is intrusive, while the porphyritic rock is extrusive.

• Both formed from magma, but one formed in a sedimentary environment.

If a mineral sample contains Fe and Mg in variable proportions, which mineral group is it likely part of?

• Carbonates

• Feldspars

• Amphiboles

• Olivines

A metamorphic rock undergoes complete melting and solidifies. The resulting rock type is:

• Sedimentary

• Metamorphic

• Igneous

• None of the above

A geologist finds a rock containing round quartz grains cemented with calcite. What environment likely produced this rock?

• A volcanic crater

• A desert sand dune

• A deep ocean trench

• A shallow marine shelf

Two minerals have the same chemical formula but different crystal structures. This phenomenon is known as:

• Polymorphism

• Cleavage

• Isomorphism

• Twinning

Which mineral is most resistant to chemical weathering, and why?

• Feldspar, because of its silicate structure

• Quartz, because it is chemically stable

• Calcite, because it reacts easily with acids

• Olivine, because it is dense

A sandstone has well-rounded grains, cross-bedding, and a high percentage of quartz. What does this indicate about its depositional environment?

• It was deposited in a high-energy river.

• It was formed in a desert environment.

• It was formed in a volcanic crater lake.

• It was deposited in a deep marine setting.

You find a fossiliferous limestone with marine shell fragments. What can you deduce about the paleoenvironment?

• A high-energy beach setting

• A calm, shallow marine environment

• A deep ocean trench

• A volcanic island environment