Licensure Exam Practice Test Questions

Certified Professional Geologist (CPG) Licensure Exam Practice Test Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

Comprehensive Practice Examination Covering All Subject Areas: Mineralogy,

Petrology, Structural Geology, Hydrogeology, Engineering Geology, Environmental Geology, Geochemistry, and Geophysics.

1. The Mohs scale of hardness is based on the ability of one mineral to:

• React with acid
• Transmit light
• Scratch another mineral
• Cleave along planes

Rationale: The Mohs scale measures relative hardness based on scratch

resistance — a harder mineral can scratch a softer one. 1 / 4

• Which mineral is most likely to effervesce when dilute hydrochloric acid is

applied?

• Quartz
• Calcite
• Feldspar
• Gypsum

Rationale: Calcite reacts with HCl due to the release of carbon dioxide from

carbonate decomposition.

3. The Earth's core is primarily composed of:

• Iron and nickel
• Silicon and aluminum
• Oxygen and magnesium
• Sodium and calcium

Rationale: Seismic and density data indicate that the core is metallic, mainly

iron with some nickel.

4. The process that converts sediments into sedimentary rock is known as:

• Weathering
• Erosion
• Lithification 2 / 4

• Metamorphism

Rationale: Lithification involves compaction and cementation of sediments

into solid rock.

• Basalt is the extrusive equivalent of which intrusive igneous rock?
• Granite
• Diorite
• Gabbro
• Peridotite

Rationale: Basalt and gabbro share the same mafic composition but differ in

cooling depth.

• Which of the following metamorphic rocks forms from limestone?
• Slate
• Marble
• Schist
• Gneiss

Rationale: Limestone recrystallizes under heat and pressure to form marble.

7. The most common mineral group in the Earth's crust is:

• Carbonates
• Silicates 3 / 4

• Oxides
• Sulfides

Rationale: Silicates dominate Earth's crust due to the abundance of silicon

and oxygen.

8. The zone of saturation in the subsurface is characterized by:

• Air-filled pores
• Water-filled pores
• Unsaturated soils
• Low permeability

Rationale: The zone of saturation contains groundwater occupying all pore

spaces.

9. Porosity is defined as:

• The rate of water flow
• The mass of solid material
• The percentage of void space in a rock or sediment
• The permeability of a medium

Rationale: Porosity measures the volume of pore space relative to the total

volume.

• / 4