The use of hot stones for healing dates back to ancient times, but it wasn't until Arizona massage therapist Mary Nelson introduced her hot stone massage technique, called LaStone Therapy, that the use of hot stones for massage caught on.
The hot stones are usually made of basalt, a type of rock that is rich in iron, so they retain heat. River rocks are normally used because they are smooth - they are smoothed over time by the river current.
Once the stones have heated sufficiently, some are placed onto specific points on the body (such as the back, hands, etc.) and others are held by the massage therapist and used to work the muscles.
Certain styles of stone massage also incorporate chilled stones into the routine. These stones are usually marble, and are placed into a bowl of iced water before use.
The heat of the stones warm and relax the muscles, which allows the therapist to apply deeper pressure, if desired.
The warmth of the hot stones improves circulation and calms the nervous system rebalancing the body and mind.