Which of the following is not an ore?

Options

A. Malachite
B. Pewter
C. Calamine
D. Cerussite

Explanation

To determine which of the following is not an ore, we will analyze each option provided in the question: Malachite, Pewter, Calamine, and Cerucite.

### Step 1: Identify the nature of each option.

1. **Malachite**:
- Malachite is known to be an ore of copper. Its chemical formula is primarily represented as Cu2CO3(OH)2. This indicates that it contains copper in a mineral form, making it an ore.

2. **Pewter**:
- Pewter is not an ore. It is an alloy primarily composed of tin (85-99%) along with small amounts of copper, antimony, and sometimes lead or silver. Since it does not contain any metal in its ore form, it is classified as an alloy rather than an ore.

3. **Calamine**:
- Calamine is an ore of zinc, with the chemical formula ZnCO3. It is a mineral that contains zinc, thus qualifying it as an ore.

4. **Cerucite**:
- Cerucite is an ore of lead, represented by the formula PbCO3. It contains lead in a mineral form, making it an ore.

### Step 2: Conclusion
After analyzing all the options, we find that:
- Malachite, Calamine, and Cerucite are all ores.
- Pewter is not an ore; it is an alloy.

Thus, the correct answer to the question "Which of the following is not an ore?" is **Pewter**.

### Final Answer:
**Pewter** is not an ore.

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