A geode is a rock cavity covered with crystals and other mineral matter. It may happen that it is not exactly reconstituted in two halves, but is broken into three pieces.
Regarding quartz crystals, they are high vibration stones. They are associated with the third eye chakra and the crown chakra. Use it to recharge your crystals. By placing them on them for a few minutes or a few hours, they receive the powerful energy released by the mineral mass and are recharged.