Which of the following is an amorphous solid?

Options

A. Graphite (G)
B. Quartz glass `(SiO_2)`
C. Chrome alum
D. Silicon carbide (SiC)

Explanation

To determine which of the following is an amorphous solid, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Options**: The question presents several materials, and we need to identify which one is an amorphous solid. The options given are graphite, quartz glass, chrome alum, and silicon carbide.

2. **Analyze Graphite**:
- Graphite is a form of carbon that has a layered structure.
- It is classified as a crystalline solid because it has a well-defined geometric arrangement of atoms.

3. **Analyze Quartz Glass**:
- Quartz is a crystalline form of silicon dioxide (SiO2).
- However, quartz glass (also known as fused silica) is produced by melting quartz and does not have a long-range order in its atomic structure.
- Therefore, quartz glass is classified as an amorphous solid.

4. **Analyze Chrome Alum**:
- Chrome alum is a type of double sulfate mineral that is typically found in a crystalline form.
- Thus, it is classified as a crystalline solid.

5. **Analyze Silicon Carbide**:
- Silicon carbide (SiC) is a compound that can form a crystalline structure.
- It is often categorized as a covalent or network solid, which means it is also crystalline.

6. **Conclusion**:
- Among the options analyzed, only quartz glass is classified as an amorphous solid.
- Therefore, the answer to the question is **quartz glass**.

### Final Answer:
The amorphous solid among the options is **quartz glass**.