How do you keep your amethyst stone from becoming dull or cloudy? The simplest method to prevent this accumulation is by routine upkeep and cleaning. The good news is that costly equipment is not needed to wear amethyst. When it comes to maintaining amethyst crystal or amethysts stone jewelry, simplicity really is key. With a Moh's hardness rating of 7, amethyst is a rather durable stone. This makes it a great choice for daily jewelry because it can tolerate a lot of wear and tear.