A crystal’s hardness often gets overlooked when it comes to factors of importance, but in magic it can make a big difference in how quickly your magic plays out. Most people use the Mohs Scale Of Mineral Hardness to determine this, although there are more precise scales for measuring this, like measuring a mineral’s “absolute hardness.” Absolute hardness ranges from a scale of 1 – 1,600, while Mohs hardness ranges from a scale of 1 – 10.
Physically speaking, a hardness scale makes comparisons by seeing which minerals can visibly scratch another mineral. For example, quartz rates as 7 on the Mohs scale, so it would definitely be able to scratch a piece of calcite which only rates 3. The higher the number, the harder the mineral. Talc is the weakest mineral on the scale, rating as 1. Diamonds are the strongest mineral on the scale, rating as 10.
Metaphysically speaking, hardness determines how quickly energy can move through a mineral. This can be very important in understand how fast a crystals work. Crystals work fairly slowly to begin with, but some do work much faster than others. For example, it is generally better to buy a wand that has a lower hardness rating, as you can move energy through them more efficiently. For example, selenite rates as 2 on the Mohs hardness scale, so it is the most fast acting wand you can own. Trust me, you wouldn’t want a wand made out of talc. A mineral rating 2 is the softest stone you would want to work with. But just because a mineral rates higher on the scale doesn’t mean you shouldn’t work with it. It’s just best to fully understand your stones so you can have proper expectations for them.