Opal (mineral with liquid inclusions) is a :

Options

A. Gel (liquid dispersed in solid phase)
B. Solid sol (solid dispersed in solid phase)
C. Sol (solid dispersed in liquid)
D. Foam (gas dispersed in liquid)

Answer

To determine the classification of opal, which is described as a mineral with liquid inclusions, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Composition of Opal**:
- Opal is primarily composed of hydrated silica (SiO₂·nH₂O). This indicates that it contains water molecules within its structure.

2. **Understand Liquid Inclusions**:
- Liquid inclusions refer to tiny pockets of liquid that are trapped within a solid mineral. In the case of opal, these inclusions are part of its hydrated structure.

3. **Classify Opal**:
- Given that opal contains liquid inclusions and is made of silica, it can be classified based on its physical state. Opal is not a pure liquid; it is a solid mineral that contains liquid inclusions.

4. **Determine the Type of Dispersion**:
- Since opal consists of a solid matrix (the silica) with liquid inclusions, it can be classified as a solid sol. In a solid sol, the solid phase is dispersed in a solid medium.

5. **Select the Correct Option**:
- Based on the classification, opal is best described as a solid sol. Therefore, the correct option is B: solid sol.

### Final Answer:
Opal is classified as a solid sol.

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