The formula of azurite is `:`

Explanation

To determine the formula of azurite, we can follow these steps:

### Step 1: Identify the Composition of Azurite
Azurite is known to be a copper mineral that is primarily composed of copper, carbonate, and hydroxide ions.

### Step 2: Understand the Chemical Components
The chemical components of azurite include:
- Copper (Cu)
- Carbonate (CO3)
- Hydroxide (OH)

### Step 3: Determine the Oxidation State of Copper
In azurite, copper is typically in the +2 oxidation state. This is important for balancing the formula.

### Step 4: Write the Basic Formula
The basic formula for azurite can be expressed as:
- 2 Copper ions (Cu) for every 1 carbonate ion (CO3) and 2 hydroxide ions (OH).

### Step 5: Combine the Components
Combining these components, we can write the formula as:
- 2CuCO3 · Cu(OH)2

### Step 6: Simplify the Formula
This can also be simplified and represented as:
- Cu3(CO3)2(OH)2

### Final Answer
Thus, the formula of azurite is:
- **Cu3(CO3)2(OH)2**

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