For cleansing and energising you can follow below method.
Cleansing is the part where you need to clean your gemstone from dirt and negative energies sticking to it.
For which, take a bowl of clean water and add three hand full of rock salt (not powdered) to it. Now take your gemstone ring or pendant and start cleaning it with rock salt crystal before it gets dissolved. And at this very moment one should be only thinking about removing negative energies from gemstone.
One may ask; why only rock salt and not detergents? For removing dirt one may use any chemical but for removing negative energies one should use rock salt as it is very good absorber of negative energies. That is why in India our grandmother and mother used rock salt and revolve around on children’s head (usually 7 times) to wear-off bad and ill energies.
Energizing: Naturally, we all have been energized by our souls. During any festivals our pandits will energize the idols with their particular deities energy, which is universal. Keeping this in mind, we have to energizes the gemstones based on their planets / dieties for which you can follow below procedure.
Each gemstone has to be energized and worn on auspicious tie pertaining to that planet. After cleansing, you need to request and pray to that particular planet’s energy to impower the gemstone. For this, hold the gemstone between thumb and ring finger only (no other finger) and start chanting the powerful mantras (verbs) pertaining to gemstone planet for some time prescribed by astrologer.
Then, take that gemstone and keep it near the idol of planet of navagraha (nine planet). Praise and honour your name and offer flowers pertaining to that planet. Now again, chant mantras holding gemstone between thumb and ring finger once more.
Now your gemstone is fully energised and before wearing pray to gemstone planet deities about your requirements / desires to get fulfilled.
Finally, wear the gemstone on the finger suggested by your astrologer and sit silently for some time so that your gemstone starts gelling-up with your body.