Classify each item as either a mineral or a rock.
gneiss, basalt
Gneiss is a rock, while basalt is also a rock.
Complete the following task based on the instruction and optional input provided.### Instruction:
Classify each item as either a mineral or a rock.

### Input:
gneiss, basalt

### Output:
Gneiss is a rock, while basalt is also a rock.