gonna have to think 'bout this...
Pure quartz has a hardness of 7. So does amorphous (non-crystalline) silica (flint, agate, etc.).
Basalt has a hardness less than that, being an assemblage of silicates.
If the cutting tool is the same as any other rock cutting tool on earth (diamond, silicon-carbide, aluminum oxide) the hardness would be 9-10.
Interesting.
Mars is so weird.