This is one of my favorite stories. I first read a version of it in a book called Legends. This expanded version of the story is as told to me by my friend Josef. The Author pulled this right from our book, Marabella; Discovering Magics. It explains the origins of the Dragon's Eye, a simple jewel with powerful magics.

THE SUNSET DRAGON

      Once the Demalions occupied a great city in the north.” He began. “The people all possessed magics. The great shadow that passed over the city every day at sunset was a mighty dragon who lived in a high cave in the mountains. One day a green eyed boy from the city braved the perilous climb and made his way to the dragon’s lair. The mighty beast watched as the boy fearlessly trudged up the dangerous slopes. He was impressed. He admired the boy’s tenacity, so he allowed the boy to reach his hidden cave.  The boy found there a massive collection of treasure.  Mounds of gold coin from many realms, great chests filled with magnificent gems and jewels, and huge pearls from the depths all were heaped into piles. The boy walked around the treasure deeper into the cave. Finally, the dragon revealed himself.  “For your bravery, I will allow you to leave with your life and all that you can carry.” The dragon told the boy. 
     “But I did not come for treasure.” The boy bravely spoke up.  “I came to ask one question.”
     “You value knowledge more than your own life?” The dragon was intrigued.

     “I suppose I do.” Said the boy.

     “Then ask your one question.” Growled the dragon.  

     “Why do you cast your shadow across our city each day at sunset, flying from east to west and back again?”

       The great dragon chuckled.  “That is what you wish to know?”

            “Yes.” The boy replied.

      The great dragon lowered his head. “I do it for love.  My love is the fiery dragon that fuels the sun. Each evening as the sun sets I fly west as far as I can go so that I might glimpse her face before she sinks below the horizon.  No matter how fast or far I fly I can never reach her, for I am earthbound.”

     “Why are you earthbound?”

     “That is another question. But, if you must know, I was mutilated in a fight with the great river and a dragon must be without blemish to shine in the heavens.” The great dragon hung his head in sorrow.  It was then that the boy noticed that the great dragon had only one emerald green eye.  “Now take your treasure and go!” The dragon roared. 

      The boy looked around at all the riches.  He was wise and truly had come only for knowledge. He knew that a bag of gold would be heavy and weigh him down. He would not likely make the dangerous climb back down the mountain. “Take your treasure and go!” The great dragon bellowed again, turning back to the depths of his cave. The boy looked and spotted a small green pebble. He reached down and slipped it into his pocket.”

“You know I’ve read this story many times.” Belle interrupted. “The city is destroyed by the dragon’s green fire when he comes looking for his dried up old eye.” 

“That is the legend.” Josef replied. “That is not the real story. May I continue?”  Belle nodded her approval. “I will consolidate the story some, since you know it.”

      The boy makes his way back to the city, now possessing the Dragon’s Eye.  His magics are without equal.  Over many winters, the boy matures, has a family, and his progeny become more and more powerful. He becomes a leader and governs the people with kindness and wisdom. Many seasons later, when he is an old man, the city is actually destroyed by a quarrel between two of his great grandsons, fighting over who would possess the stone when the old man died. The legendary green fire which laid waste to the city was theirs. Only those with the emerald green eyes possess the green dragon’s fire.  With the city in rubble, the clans dispersed.

     “That is the real story.” Josef concluded.