Even though this is a common purification method, our company does not recommend using gravel to purify crystals. Generally, gravel itself is just ordinary crystal and does not have any special purification effects. Sometimes you may find that the crystal looks more beautiful after using gravel, giving you the illusion of successful purification. In fact, because crystals have the ability to absorb information, "clean" gravel, being a type of crystal, when placed with a crystal that has negative energy, will cause a permeation effect. The negative energy will transfer from the crystal to the gravel until their negative energy levels are equal, at which point the effect stops. Therefore, this method cannot completely remove negative energy from the crystal. An equal amount of gravel can only absorb about half of the negative energy. Furthermore, once the gravel has absorbed this negative energy, it cannot dissipate it on its own, so it cannot be used for any further "purification" after the first use.