Each of these minerals can be scratched by the one above it and will scratch the ones below it. Minerals of the same hardness won’t scratch each other. Quartz, which is the hardest mineral that is commonly air born, is on the scale of 7. It is neccesary to considered the jewelry with gemstones in it that have a Mohs below 7 because of the amount of dust and impurities in the air. If the dust contains tiny particles of Quartz, then any other minerals that sit below quartz on the MOHS scale will be scratched. So to be concluded , the hardness in mohs scale is about the resistable or durable from scratching