An unknown mineral scratches apatite and is scratched by corundum. what can you conclude about this mineral’s hardness?

If we guide ourselves with the Moh´s scale:

Material scratches apatite → material is harder than 5.

Material is scratched by corundum → material is softer than 9.

Conclusion:

The hardness of the unknown material stands between 5 and 9.

Note:  

Both apatite and corundum are defining materials (reference materials in the Moh´s scale). So, you can also give an answer using defining materials:

"It can either be an orthoclase feldspar, a quartz or a topaz".

Hope it helped,

BiologiaMagister

This answer is dedicated to JaySL

not sure but try c two haploid cells

explanation: