Stones must be cleaned regularly (once a week) so that their power, purity, strength and vibration is not impeded. Stones will absorb your negative energies which is part of their function. And that will reduce their potency or cause them to stop vibrating altogether.

You can clean them by using a small horseshoe magnet and passing the two poles of the magnet back and forth above the stone for 15 to 30 seconds. Old stones, jewelry and heirlooms should initially be cleaned for 2 full minutes.

Magnets are available from a hardware store or hobby shop. Or you can clean the stone by burying it in salt overnight.