Tibetan Folk Tales, by A.L. Shelton, [1925], at sacred-texts.com
During the dark of the moon the robber can steal the yak's calf.
Tibetan Proverb.
ONCE upon a time there was a king who had a great diamond which he admired very much; he liked to let the sun shine on it and see it sparkle. But he had some servants who were very dishonest and who decided to rob him of the jewel. So that there would be no suspicion attached to them, the servants decided that they would make the jewel disappear while the king was looking at it. It was the king's custom to have it taken out in the light so that he might see all the colors of the rainbow in it. This day he took the jewel out and placed it quite a distance away, and as he looked at it, it shone and shone, but the sparks seemed to get less and less and it finally disappeared before his eyes. He and his servants went to look for it but they could find nothing, because they had used a piece of ice to deceive him. The king lost his great jewel; it had vanished before his eyes, and the blame could be placed upon no one.