Question

Which of the following minerals possesses more electrical resistivity?

• A. quartz
• B. granite
• C. mica
• D. basalt

Hint:

Quartz is highly resistive and is often used in electronics for insulation.

Answer 1

The Correct Option is A

To determine which mineral possesses the highest electrical resistivity, let's analyze the electrical properties of each option:

1. Understanding Electrical Resistivity in Minerals:
Electrical resistivity (measured in Ω·m) indicates how strongly a material opposes electric current flow. Higher values mean better insulation properties.

2. Resistivity Comparison:

Mineral	Resistivity Range (Ω·m)	Structural Features
Quartz	1012 to 1016	Framework silicate with strong covalent bonds
Granite	103 to 105	Composite rock with conductive minerals
Mica	1011 to 1013	Sheet silicate with some ion mobility
Basalt	102 to 104	Contains iron-rich minerals

3. Why Quartz Has Highest Resistivity:

• Perfect SiO₄ tetrahedral framework leaves no free ions
• Wide bandgap (9 eV) prevents electron excitation
• Lacks metallic impurities or conductive pathways

4. Limitations of Other Minerals:

• Granite/Basalt: Contain conductive minerals like biotite or magnetite
• Mica: Sheet structure allows some ionic conduction

5. Experimental Evidence:
Laboratory measurements show:

• Pure quartz crystals achieve >10¹⁵ Ω·m at room temperature
• Even milky quartz maintains >10¹² Ω·m
• Conductivity increases only at very high temperatures (>500°C)

Final Answer:
The mineral with the highest electrical resistivity is quartz.