Which of the following is not an ore?

Options

A. Corundum
B. Zincite
C. Calamine
D. Chromite

Explanation

To determine which of the given options is not an ore, we will analyze each substance mentioned in the question.

### Step-by-Step Solution:

1. **Identify Corundum**:
- Corundum has the chemical formula Al₂O₃ (aluminum oxide).
- It is derived from bauxite, which is an ore of aluminum.
- Therefore, corundum itself is not classified as an ore.

2. **Identify Zincite**:
- Zincite is known as the ore of zinc and has the chemical formula ZnO (zinc oxide).
- Since it is a source of zinc, it is classified as an ore.

3. **Identify Calamine**:
- Calamine is a term used for a mixed ore that contains both iron and zinc, with the chemical formulas Fe₂O₃ (iron oxide) and ZnO (zinc oxide).
- As it contains valuable metals, calamine is also classified as an ore.

4. **Identify Chromite**:
- Chromite is the ore of chromium, with the chemical formula CrFeO₄ (chromium iron oxide).
- Since it is a source of chromium, chromite is classified as an ore.

5. **Conclusion**:
- After analyzing all the substances, we conclude that out of the options provided, **corundum (Al₂O₃)** is not an ore.

### Final Answer:
Corundum is not an ore.

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