Corundum is an ore of aluminium.

Explanation

To determine whether the statement "Corundum is an ore of aluminium" is true or false, we can follow these steps:

### Step 1: Identify Corundum
Corundum is a mineral composed primarily of aluminium oxide, with the chemical formula Al₂O₃.

### Step 2: Understand the Composition
Corundum consists of aluminium (Al) and oxygen (O) atoms. The presence of aluminium in its chemical formula indicates that it is a source of aluminium.

### Step 3: Define Ore
An ore is a naturally occurring solid material from which a metal or valuable mineral can be extracted profitably. Since corundum contains aluminium, it qualifies as an ore of aluminium.

### Step 4: Evaluate Hardness
Corundum is known for its hardness, rated at 9 on the Mohs scale. This characteristic does not affect its status as an ore but highlights its durability and potential uses beyond just being an ore.

### Step 5: Conclusion
Since corundum (Al₂O₃) contains aluminium and is a naturally occurring mineral from which aluminium can be extracted, we can conclude that the statement "Corundum is an ore of aluminium" is true.

### Final Answer
**True** - Corundum is indeed an ore of aluminium.

---