The Gems, three of them, are special to Ryoko. Without them she doesn't have her complete power, and with them Ryoko is one of the most powerful people in the universe. The gems taken from her by Yosho, after being chased by him for causing havoc on Planet Jurai. Yosho took the gems by stabbing Ryoko in the thoat with his sword, and they sucked them out of her. The gems were now trapped with the sword, which Ryoko could not touch; or she would be shocked. After Tenchi mistakingly released Ryoko from her cell in the caves, he was attacked by her becuase he was related to Yosho. And he had the sword that still had the gems trapped within. Ryoko couldn't touch the sword so she had to get Tenchi to give them to her somehow. Well she half succeeded, Tenchi gave her two of the three gems. One last thing, two of the gems go to her wrist(one for each), I can't remember where the other on goes. Below will be some of the things that Ryoko can do with two or all three of the gems.

There are a couple of things that Ryoko can do with the gems. She can create a Light Beam Sword, Light Beam Blasts, and summon a demon that she can't really control.

The Light Sword is pretty much just a sword that Ryoko can create with her energy. t is very powerful and pretty much cut through anything.

The Light Beam Blast is a build up in Ryoko's power, until she decides to release it in a blast. This attack is extremely powerful, and can take out a large area. To really imagine how powerful it is, think of Dragonball Z and the attacks in that.

The Demon that Ryoko can release, is even more powerful then Ryoko. She doesn't release it all to often, mostly because she can't control it. She released it once and it destroyed almost all of Tenchi's house, and took all Ryoko had to seal it back up. Ryoko can only release the demon if she has all of the three gems, because she has to have all her power.