The legend of Amethyst is based on "Amethyst, Story of Bacchus" a story written in the 16th century. It is about the Greek god of wine named Bacchus. In this story, Bacchus is a menace who has no admirable qualities.
One day, the gods scolded him about his servants, the Leopards who were always drunk. Bacchus did not repent and, in anger, planned to feed the first person he met to the Leopards. Just as he passed the palace of the moon goddess Diana, he saw Amethyst, a young maiden that worked in the palace. Amethyst was a god-fearing nymph who the gods were very proud of.
Out of spite, Bacchus ordered his servants to attack Amethyst. When Amethyst saw she was about to be attacked she called to Diana for help. When Diana heard her cry she turned Amethyst into a transparent stone to protect her. Bacchus stared at the transparent stone that used to be Amethyst, and ashamed of his anger, he wept tears of wine that fell upon the transparent stone and turned it into the color of grapes.