A good thing of cause would be to first wash it and run it through clear water. Then you want to burn some white sage. And pass your piece through the smoke. Now it is ready to charge.
Rub your hands together until they get slightly warm. Place the piece in the center of your palm and then place your other hand on top. Focus your thoughts and energy sending what you wish your pendant to carry into your piece.That can be Protection/Love/Peace/Strength/Focus, It is up to you. Once you can feel that you sent enough energy into it - immediately put it on. For at least 3 days do not take it off. This will seal it. It's now yours.
You can also do this when giving a special present to someone.