Write two physical properties of Diamond.

Explanation

**Step-by-Step Solution:**

1. **Understanding Diamond:**
- Diamond is an allotrope of carbon, meaning it is a different structural form of the same element.
- It has a unique structure characterized by sp3 hybridization, which leads to a tetrahedral arrangement of carbon atoms.

2. **Physical Property 1: Hardness**
- One of the most notable physical properties of diamond is its hardness.
- Diamond is known as the hardest natural substance on Earth due to its strong covalent bonds and the arrangement of carbon atoms in a three-dimensional network.

3. **Physical Property 2: Electrical Conductivity**
- Another important physical property of diamond is its electrical conductivity.
- Diamond has poor electrical conductivity because it lacks free electrons. The carbon atoms in diamond are tightly bonded, which prevents the movement of electrons.

**Final Answer:**
1. Diamond is the hardest natural substance.
2. Diamond has poor electrical conductivity.

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