The action of holding the stone between your index finger and thumb and gently moving your thumb back and forth across it can create a since of relaxation and calmness. Doing this during meditation helps to center your concentration making your meditation even more beneficial.
The use of worry/calming stone has many origins as a folk practice implement. It is also called by several names such as: palm stones, thumb stones, fidget stones, soothing stones, or sensory stones.
Calming stones are great to keep with you because they are multi-functional. Calming, relaxing and focusing from the act of rubbing the stone as well as the properties of the stone its self. Choosing a stone for its properties based on your needs and rubbing it while thinking of your desires can help you focus your thoughts into your intentions.
Variations on the concept originate in ancient Greece, Tibet, Ireland, and multiple Native American tribes. The concept of a worry stone began by the simple action of picking a smooth stone and fiddling with it. Worry stones made by sea water were generally used by Ancient Greeks. Native American tribes would continuously give them to younger generations, creating a sense of connection from previous family members.
In Ireland, worry stones are made from Connemara marble. Rubbing a piece of Connemara marble is said to make worries disappear and to bring good luck. Connemara Marble is a green-veined, serpentine-rich stone from that region.