Crystal of Neahtid

The Crystal of Neahtid is powerful instrument of Magic featured on the BBC series Merlin. It holds the secret to time itself. According to The Great Dragon, the crystal can only be wielded by powerful sorcerers such as Mordred and Merlin himself. It allows the user to see either the past, present or future. According to Kilgharrah, a powerful witch like Morgana would not have the power to use it.  However, he likely meant she wasn't powerful enough to use crystal itself yet or just staying that because of Kilgharrah's hatred towards Morgana. 
== History ==
The crystal of Neahtid was forged from the Crystal Cave. During the Great Purge, many sorcerers we're killed protecting it. The Crystal was eventually found by Uther's men and the king had it hidden in the Vaults of Camelot 
Roughly 20 years later, the magical user, Alvarr learned of the Crystal's capabilities and whereabouts. He and Mordred manipulated Morgana into stealing the crystal from the Vaults of Camelot. She gave them to Alvarr, who hoped Mordred would be able to identity Uther's weakness. However, Morgana was followed by Merlin, who informed Gaius of Alvarr's plot. They later informed Uther of the crystal's whereabouts. Arthur Pendragon led a raid on Alvarr's camp and was able to restore the crystal. He text Merlin with protecting it but the young warlock refused to hold it due to feeling overwhelmed by it's power. Later in the night, Merlin failed in resisting the temptation to look at it and took the crystal out of its pouch. As he used his magic, Merlin saw a vision from the Crystal, warning him of what would happen if he unleashed the Great Dragon. Terrified, Merlin threw the crystal on the floor, haunted by the visions. 
Presumably, the crystal was returned to the Vaults when Merlin, Arthur and the Knights returned. 
At least a year later, Merlin came into the Crystal Cave after being guided by the spirit of Taliesin, who revealed that the crystal came from here. 
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