Which one of the following minerals is formed by decomposition of rocks, leaving a residual mass of weathered material?
(a) coal
(b) bauxite
(c) gold
(d) zinc
Answer:
(b) Bauxite ✅
Explanation:
Bauxite is formed through the weathering and decomposition of rocks. This process removes soluble materials, leaving behind a residual deposit rich in aluminum. Over time, due to chemical weathering, aluminum-rich minerals accumulate, forming bauxite.
Points:
- Residual mineral: Formed in place by rock weathering.
- Rich in aluminum: Used for aluminum extraction.
- Common in tropical regions: Found in India, Australia, and Brazil.
Bauxite is an important ore of aluminum and is primarily formed through rock decomposition, making it a residual mineral deposit. 🌍⛏️