Which one contains both Ca and Mg ?

Options

A. Limestone
B. Dolomite
C. Chalk
D. Feldspar

Answer

To determine which option contains both calcium (Ca) and magnesium (Mg), we can analyze the chemical composition of each option provided:

1. **Limestone**:
- Limestone primarily consists of calcium carbonate (CaCO₃).
- It does not contain magnesium.

2. **Dolomite**:
- Dolomite is a mineral that consists of calcium magnesium carbonate, represented by the formula CaMg(CO₃)₂.
- This means it contains both calcium and magnesium.

3. **Chalk**:
- Chalk is a form of limestone and is primarily composed of calcium carbonate (CaCO₃).
- It does not contain magnesium.

4. **Feldspar**:
- Feldspar is a group of minerals that do not typically contain significant amounts of calcium or magnesium.
- It is primarily composed of aluminum silicates.

Based on this analysis, the only option that contains both calcium and magnesium is:

**Answer: Dolomite (Option 2)**