Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:
a piece of rock

Explanation

To classify a piece of rock as opaque or transparent, and luminous or non-luminous, we can follow these steps:

### Step 1: Determine if the object is opaque, transparent, or translucent.
- **Opaque Objects**: These do not allow light to pass through them.
- **Transparent Objects**: These allow light to pass through clearly, enabling a clear image to be seen.
- **Translucent Objects**: These allow some light to pass through but scatter it, resulting in a blurry image.

**Conclusion for Step 1**: A piece of rock does not allow light to pass through it, which means it is classified as **opaque**.
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