The pendant by itself is not the Jewel of the Crown, but the agate bead is really one of a kind: after the cutting task, an ancient lapidary noticed the hole you can also see, and beyond it a small cave, its walls covered with quartz crystals: a geode. Thus, to allow the light to come in, he made a tiny extra perforation from de main X shaped bead perforation.
The very clear crystal beads do not stop a well directed ray of light to dispell the aeons-old darkness of the inner space. You (aided perhaps by a jeweller's magnifier) are then welcome into a mind-blowing natural shrine...
A good trip, indeed.