I have often experienced a sense of energy from a particular gemstone ring, bracelet or necklace.  I've also been drawn to pick up and hold rough stones - whether I found them along a trail in the mountains, a path in the city or a box of rocks in a store, certain stones just seemed to draw me to them.   The transfer of energy from natural stones to the human body is an ancient concept.  Gemstones originate from hot magma inside the earth.  Gemstones are formed from dust, sand, chemical substances and acids that have dissolved in water.  The art of healing with stones is thousands of years old.  Gemstones were also considered to have protective and talismanic properties and to keep evil spirits away.  This ancient knowledge has been passed down to our day.  Gemstones are divided into three basic categories: rough stones taken from the original rock and allowed to remain in their natural condition.  Being free from the imprint of human workmanship, unbridled energy flows through them and they possess the greatest healing power.  It is recommended that rough stones be placed directly upon the body.  The second category is tumbled stones.  For this type of gemstone, rough stones are put together  with water and sand in a drum that is then turned.  Tumbled stones are rounded with smooth surfaces and are often used as touchstones.  They are best suited to be laid or pressed onto the body.  By holding and rubbing these stones, their energy passes through the hand and the entire body becomes infused with their power.  The third major category is gemstones which are made into jewelry.  The precious metals in which they are set can increase the energy level of the stone.  Gold settings will enhance the power of every stone.  Silver strengthens the vibratory intensity of coral and turquoise.  Single stones are best used in jewelry, multiple stones should be worn as necklaces, armbands or on key rings.  Source:
Healing Crystals and Gemstones by Dr. Flora Peschek-Bohmer and Gisela Schreiber.  The next time you are in an environment that allows you to hold different stones in your hand, try tuning into the various energies they produce - who knows, you might have another excuse for a new ring!