mineral whose formula is

Options

A. `CaMg (CO_(3))_(2)`
B. `MgCO_(3)`
C. `CaCO_(3).MgCO_(3)`
D. `MgSO_(4).7H_(2)O`

Explanation

**Step-by-Step Solution:**

1. **Identify the Mineral**: The question asks for the formula of a mineral. In this case, we are focusing on dolomite.

2. **Recall the Chemical Composition**: Dolomite is a mineral composed primarily of calcium and magnesium carbonates. Its chemical formula is derived from these components.

3. **Write the Formula**: The chemical formula for dolomite is \( \text{CaCO}_3 \cdot \text{MgCO}_3 \). This indicates that dolomite consists of calcium carbonate and magnesium carbonate.

4. **Check the Options**: If there are multiple-choice options given, identify which option matches the formula \( \text{CaCO}_3 \cdot \text{MgCO}_3 \).

5. **Select the Correct Option**: Based on the options provided, select the one that corresponds to the formula of dolomite. In this case, it is noted that the correct answer is the third option.

6. **Conclude**: Therefore, the formula of the mineral dolomite is \( \text{CaCO}_3 \cdot \text{MgCO}_3 \).

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