Which of the following is not an ore:

Options

A. malachite
B. calamine
C. stellite
D. cerussite

Answer

To determine which of the following options is not an ore, we need to analyze each option provided. An ore is defined as a naturally occurring solid material from which a metal or valuable mineral can be extracted profitably.

### Step-by-Step Solution:

1. **Identify the options**: We need to evaluate the given options to see which one is not classified as an ore.

2. **Evaluate Malachite**:
- Malachite is known as an ore of copper.
- Its chemical formula is Cu2CO3(OH)2.
- Since it contains copper and can be economically extracted, it qualifies as an ore.

3. **Evaluate Calamine**:
- Calamine is recognized as an ore of zinc.
- Its chemical formula is ZnCO3.
- Like Malachite, it contains a valuable metal that can be extracted, so it is also classified as an ore.

4. **Evaluate Stellite**:
- Stellite is not an ore; it is a cobalt-chromium alloy.
- It is primarily used for its wear resistance properties and does not contain a metal that can be extracted from a natural state.
- Therefore, Stellite does not qualify as an ore.

5. **Evaluate Kerosite**:
- Kerosite is known as an ore of lead.
- Its chemical formula is PbCO3.
- Since it contains lead and can be extracted profitably, it is classified as an ore.

6. **Conclusion**:
- Among the options evaluated, Stellite is the only one that is not an ore.
- Hence, the answer is **Stellite**.

### Final Answer:
The option that is not an ore is **Stellite**.