Which of the following is a solid sol?

Options

A. Butter
B. Paint
C. Gemstone
D. Cake

Answer

To determine which of the following options is a solid sol, we first need to understand what a solid sol is.

### Step-by-Step Solution:

1. **Definition of Solid Sol**:
- A solid sol is a type of colloidal dispersion where solid particles are dispersed in a solid medium. It is characterized by its soft nature and can become softer when heated.

2. **Identifying Characteristics**:
- Solid sols are typically soft and can be altered in consistency when subjected to heat (boiling for a few minutes).

3. **Analyzing the Options**:
- We need to look at the options provided in the question to identify which one fits the definition of a solid sol.

4. **Identifying Gemstones**:
- Among the options, gemstones are known to be solid materials that can contain tiny inclusions or impurities, which can be considered as a colloidal dispersion within the solid structure.

5. **Conclusion**:
- Based on the understanding of solid sols and the characteristics of gemstones, we conclude that gemstones are indeed a type of solid sol.

Thus, the correct answer is **option C: Gemstone**.