|Appearances:||The Crystal Cave|
The Diamond of the Day: Part One
The crystals within the cave had the power to show those who looked into them potential futures, Taliesin credited his powers of prophecy to the cave, and it is the place where the Crystal of Neahtid was hewn from.
After Arthur and Merlin were chased into the Valley of the Fallen Kings, Taliesin showed Merlin the cave, where he saw visions of Lady Morgana killing Uther Pendragon with an ornate dagger. He attempted to avert this future but did so with disastrous consequences, and ended with him in fact causing it. However, he forgot about the first prophecy that he saw, which depicted Morgana as queen, or simply thought of it as a possible future, since Gaius said "the Crystals are treacherous" (The Crystal Cave).
Diamond of the Day (Part 1)
After Merlin lost his magical abilities due to a beast summoned by Morgana devouring his magic, Merlin travelled beside Gwaine towards the cave, before bidding farewell to Gwaine and entering the cave by himself. However, Morgana confronts Merlin within the cave's depths, after a maiden Gwaine rescued from Morgana's ambush on Camelot, Eira, traitorously informed her of Merlin's magic-rebirth attempt. Morgana obstructed Merlin by casting the cave's rocks upon Merlin, thus hindering the journey.
Merlin collapses and abruptly gives up involving himself with even Arthur's commenced war with Morgana.
Waking up, he realises a glowering entrance above, clambering recklessly towards it. He collapses yet again after reaching the entrance. The viewer, however, can notice a crystal-filled cave.
He then wakes up to notice a soul-like depiction of Merlin's father, Balinor, and Merlin asks him 'Are you alive? Are you real?' within the conversation with his father. Balinor replies by quoting 'dead or alive, real or imagined, past or present, these things are of no consequence.' But Merlin sees no reason to go on, believing the battle to be over and Morgana to have won. But his father reassures him telling him 'do not let go, do not give in'. Merlin, however, is not convinced so Balinor says to him 'If you let hope into your heart, Morgana cannot be victorious.' Merlin questions the hope without his magic. His father tells him 'You are more than the son of your father, you are the son of the earth, the sea, the sky. Magic is the fabric of this world, and you were born of that magic, you are magic itself, you cannot lose what you are.' After asking how he will find himself again Balinor tells him to 'Believe Merlin, believe what your heart knows to be true, that you have always been and always will.' He then allows Merlin to rest telling him that he will 'awaken into the light.'
Merlin awoke healed and bearing his magical abilities. He tests this by producing a butterfly from his hands. He examines what Arthur is doing through a crystal, and advises Arthur telepathically. Finally, he bids farewell to his father, however, his father responds by saying that he will always be with him, he also says that Merlin wields a power he cannot yet conceive of and that only at the heart of the crystal cave will Merlin's true self be revealed. He tells him To 'not be afraid' and to 'trust in what you are, trust in what will be.' Merlin exits the cave, in the form of Emrys.